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Sample records for human c-myc p2

  1. c-Myc-Dependent Cell Competition in Human Cancer Cells.

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    Patel, Manish S; Shah, Heta S; Shrivastava, Neeta

    2017-07-01

    Cell Competition is an interaction between cells for existence in heterogeneous cell populations of multicellular organisms. This phenomenon is involved in initiation and progression of cancer where heterogeneous cell populations compete directly or indirectly for the survival of the fittest based on differential gene expression. In Drosophila, cells having lower dMyc expression are eliminated by cell competition through apoptosis when present in the milieu of cells having higher dMyc expression. Thus, we designed a study to develop c-Myc (human homolog) dependent in vitro cell competition model of human cancer cells. Cells with higher c-Myc were transfected with c-myc shRNA to prepare cells with lower c-Myc and then co-cultured with the same type of cells having a higher c-Myc in equal ratio. Cells with lower c-Myc showed a significant decrease in numbers when compared with higher c-Myc cells, suggesting "loser" and "winner" status of cells, respectively. During microscopy, engulfment of loser cells by winner cells was observed with higher expression of JNK in loser cells. Furthermore, elimination of loser cells was prevented significantly, when co-cultured cells were treated with the JNK (apoptosis) inhibitor. Above results indicate elimination of loser cells in the presence of winner cells by c-Myc-dependent mechanisms of cell competition in human cancer cells. This could be an important mechanism in human tumors where normal cells are eliminated by c-Myc-overexpressed tumor cells. J. Cell. Biochem. 118: 1782-1791, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  2. Nuclear localization of phosphorylated c-Myc protein in human tumor cells.

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    C. Soldani

    2010-05-01

    Full Text Available Using immunocytochemical techniques at light and electron microscopy, we analysed the distribution of phosphorylated c-Myc in actively proliferating human HeLa cells. The distribution pattern of c-Myc was also compared with those of other ribonucleoprotein (RNP-containing components (PANA, hnRNP-core proteins, fibrillarin or RNP-associated nuclear proteins (SC-35 splicing factor. Our results provide the first evidence that phosphorylated c-Myc accumulates in the nucleus of tumor cells, where it colocalizes with fibrillarin, both in the nucleolus and in extranucleolar structures.

  3. XPC Promotes Pluripotency of Human Dental Pulp Cells through Regulation of Oct-4/Sox2/c-Myc

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    Lu Liu

    2016-01-01

    Full Text Available Introduction. Xeroderma pigmentosum group C (XPC, essential component of multisubunit stem cell coactivator complex (SCC, functions as the critical factor modulating pluripotency and genome integrity through interaction with Oct-4/Sox2. However, its specific role in regulating pluripotency and multilineage differentiation of human dental pulp cells (DPCs remains unknown. Methods. To elucidate the functional role XPC played in pluripotency and multilineage differentiation of DPCs, expressions of XPC in DPCs with long-term culture were examined by real-time PCR and western blot. DPCs were transfected with lentiviral-mediated human XPC gene; then transfection rate was investigated by real-time PCR and western blot. Cell cycle, apoptosis, proliferation, senescence, multilineage differentiation, and expression of Oct-4/Sox2/c-Myc in transfected DPCs were examined. Results. XPC, Oct-4, Sox2, and c-Myc were downregulated at P7 compared with P3 in DPCs with long-term culture. XPC genes were upregulated in DPCs at P2 after transfection and maintained high expression level at P3 and P7. Cell proliferation, PI value, and telomerase activity were enhanced, whereas apoptosis was suppressed in transfected DPCs. Oct-4/Sox2/c-Myc were significantly upregulated, and multilineage differentiation in DPCs with XPC overexpression was enhanced after transfection. Conclusions. XPC plays an essential role in the modulation of pluripotency and multilineage differentiation of DPCs through regulation of Oct-4/Sox2/c-Myc.

  4. XPC Promotes Pluripotency of Human Dental Pulp Cells through Regulation of Oct-4/Sox2/c-Myc.

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    Liu, Lu; Peng, Zhengjun; Xu, Zhezhen; Wei, Xi

    2016-01-01

    Introduction. Xeroderma pigmentosum group C (XPC), essential component of multisubunit stem cell coactivator complex (SCC), functions as the critical factor modulating pluripotency and genome integrity through interaction with Oct-4/Sox2. However, its specific role in regulating pluripotency and multilineage differentiation of human dental pulp cells (DPCs) remains unknown. Methods. To elucidate the functional role XPC played in pluripotency and multilineage differentiation of DPCs, expressions of XPC in DPCs with long-term culture were examined by real-time PCR and western blot. DPCs were transfected with lentiviral-mediated human XPC gene; then transfection rate was investigated by real-time PCR and western blot. Cell cycle, apoptosis, proliferation, senescence, multilineage differentiation, and expression of Oct-4/Sox2/c-Myc in transfected DPCs were examined. Results. XPC, Oct-4, Sox2, and c-Myc were downregulated at P7 compared with P3 in DPCs with long-term culture. XPC genes were upregulated in DPCs at P2 after transfection and maintained high expression level at P3 and P7. Cell proliferation, PI value, and telomerase activity were enhanced, whereas apoptosis was suppressed in transfected DPCs. Oct-4/Sox2/c-Myc were significantly upregulated, and multilineage differentiation in DPCs with XPC overexpression was enhanced after transfection. Conclusions. XPC plays an essential role in the modulation of pluripotency and multilineage differentiation of DPCs through regulation of Oct-4/Sox2/c-Myc.

  5. Evolutionarily conserved regions of the human c-myc protein can be uncoupled from transforming activity

    International Nuclear Information System (INIS)

    Sarid, J.; Halazonetis, T.D.; Murphy, W.; Leder, P.

    1987-01-01

    The myc family of oncogenes contains coding sequences that have been preserved in different species for over 400 million years. This conservation (which implies functional selection) is broadly represented throughout the C-terminal portion of the human c-myc protein but is largely restricted to three cluster of amino acid sequences in the N-terminal region. The authors have examined the role that the latter three regions of the c-myc protein might play in the transforming function of the c-myc gene. Several mutations, deletions and frameshifts, were introduced into the c-myc gene, and these mutant genes were tested for their ability to collaborate with the EJ-ras oncogene to transform rat embryo fibroblasts. Complete elimination of the first two N-terminal conserved segments abolished transforming activity. In contrast, genes altered in a portion of the second or the entire third conserved segment retained their transforming activity. Thus, the latter two segments are not required for the transformation process, suggesting that they serve another function related only to the normal expression of the c-myc gene

  6. Acidosis Decreases c-Myc Oncogene Expression in Human Lymphoma Cells: A Role for the Proton-Sensing G Protein-Coupled Receptor TDAG8

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    Zhigang Li

    2013-10-01

    Full Text Available Acidosis is a biochemical hallmark of the tumor microenvironment. Here, we report that acute acidosis decreases c-Myc oncogene expression in U937 human lymphoma cells. The level of c-Myc transcripts, but not mRNA or protein stability, contributes to c-Myc protein reduction under acidosis. The pH-sensing receptor TDAG8 (GPR65 is involved in acidosis-induced c-Myc downregulation. TDAG8 is expressed in U937 lymphoma cells, and the overexpression or knockdown of TDAG8 further decreases or partially rescues c-Myc expression, respectively. Acidic pH alone is insufficient to reduce c-Myc expression, as it does not decrease c-Myc in H1299 lung cancer cells expressing very low levels of pH-sensing G protein-coupled receptors (GPCRs. Instead, c-Myc is slightly increased by acidosis in H1299 cells, but this increase is completely inhibited by ectopic overexpression of TDAG8. Interestingly, TDAG8 expression is decreased by more than 50% in human lymphoma samples in comparison to non-tumorous lymph nodes and spleens, suggesting a potential tumor suppressor function of TDAG8 in lymphoma. Collectively, our results identify a novel mechanism of c-Myc regulation by acidosis in the tumor microenvironment and indicate that modulation of TDAG8 and related pH-sensing receptor pathways may be exploited as a new approach to inhibit Myc expression.

  7. Immortalization of human neural stem cells with the c-myc mutant T58A.

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    Lidia De Filippis

    Full Text Available Human neural stem cells (hNSC represent an essential source of renewable brain cells for both experimental studies and cell replacement therapies. Their relatively slow rate of proliferation and physiological senescence in culture make their use cumbersome under some experimental and pre-clinical settings. The immortalization of hNSC with the v-myc gene (v-IhNSC has been shown to generate stem cells endowed with enhanced proliferative capacity, which greatly facilitates the study of hNSCs, both in vitro and in vivo. Despite the excellent safety properties displayed by v-IhNSCs--which do not transform in vitro and are not tumorigenic in vivo--the v-myc gene contains several mutations and recombination elements, whose role(s and effects remains to be elucidated, yielding unresolved safety concerns. To address this issue, we used a c-myc T58A retroviral vector to establish an immortal cell line (T-IhNSC from the same hNSCs used to generate the original v-IhNSCs and compared their characteristics with the latter, with hNSC and with hNSC immortalized using c-myc wt (c-IhNSC. T-IhNSCs displayed an enhanced self-renewal ability, with their proliferative capacity and clonogenic potential being remarkably comparable to those of v-IhNSC and higher than wild type hNSCs and c-IhNSCs. Upon growth factors removal, T-IhNSC promptly gave rise to well-differentiated neurons, astrocytes and most importantly, to a heretofore undocumented high percentage of human oligodendrocytes (up to 23%. Persistent growth-factor dependence, steady functional properties, lack of ability to generate colonies in soft-agar colony-forming assay and to establish tumors upon orthotopic transplantation, point to the fact that immortalization by c-myc T58A does not bring about tumorigenicity in hNSCs. Hence, this work describes a novel and continuous cell line of immortalized human multipotent neural stem cells, in which the immortalizing agent is represented by a single gene which, in

  8. Expression of c-myc and c-fos and binding sites for estradiol and progesterone in human pituitary tumors.

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    Machiavelli, G A; Rivolta, C M; Artese, R; Basso, A; Burdman, J A

    1998-12-01

    We studied the concentration of mRNA from the oncogenes c-myc and c-fos in human pituitary adenomas by Northern blot hybridization (35 somatotrophinomas, 9 prolactinomas, 21 nonsecreting and 3 adrenocorticotrophinomas). The concentration of estrogens and progesterone receptors was also investigated. The levels of c-myc and c-fos mRNA was higher in nonsecreting tumors which were generally the largest and had a higher percentage of recurrence after surgery than the other groups. High concentration of estrogen receptors was observed in tumors derived from cells which are normally the target of this hormone, mainly prolactinomas. They were also present in somatotrophic and nonsecreting adenomas, related to the presence of prolactin or gonadotrophin cells in these tumors. The presence of estrogen receptors indicates that the tumor cells maintain their differentiation and a good prognosis as is the case for prolactinomas. We did not find any relationship between estrogen receptors and the concentration of c-myc and c-fos oncogenes. Larger adenomas (mainly nonsecreting) had higher levels of c-myc and c-fos mRNA than the other tumors and they had an important percentage of recurrence after surgery. It is clear that tumor size is related to the outcome after surgery and that nonsecreting adenomas are usually large because of the late diagnosis. However two large somatotrophinomas with extrasellar expansion also had overexpression of both oncogenes and both relapsed after surgery.

  9. The small Rho GTPase Rac1 controls normal human dermal fibroblasts proliferation with phosphorylation of the oncoprotein c-myc

    International Nuclear Information System (INIS)

    Nikolova, Ekaterina; Mitev, Vanio; Zhelev, Nikolai; Deroanne, Christophe F.; Poumay, Yves

    2007-01-01

    Proliferation of dermal fibroblasts is crucial for the maintenance of skin. The small Rho GTPase, Rac1, has been identified as a key transducer of proliferative signals in various cell types, but in normal human dermal fibroblasts its significance to cell growth control has not been studied. In this study, we applied the method of RNA interference to suppress endogenous Rac1 expression and examined the consequences on human skin fibroblasts. Rac1 knock-down resulted in inhibition of DNA synthesis. This effect was not mediated by inhibition of the central transducer of proliferative stimuli, ERK1/2 or by activation of the pro-apoptotic p38. Rather, as a consequence of the suppressed Rac1 expression we observed a significant decrease in phosphorylation of c-myc, revealing for the first time that in human fibroblasts Rac1 exerts control on proliferation through c-myc phosphorylation. Thus Rac1 activates proliferation of normal fibroblasts through stimulation of c-myc phosphorylation without affecting ERK1/2 activity

  10. Encapsulation of c-myc antisense oligodeoxynucleotides in lipid particles improves antitumoral efficacy in vivo in a human melanoma line.

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    Leonetti, C; Biroccio, A; Benassi, B; Stringaro, A; Stoppacciaro, A; Semple, S C; Zupi, G

    2001-06-01

    Phosphorothioate c-myc antisense oligodeoxynucleotides [S]ODNs (free INX-6295) were encapsulated in a new liposome formulation and the antitumor activity was compared to the unencapsulated antisense in a human melanoma xenograft. The systemic administration of INX-6295 encapsulated in stabilized antisense lipid particles (SALP INX-6295) improved plasma AUC (area under the plasma concentration-time curve) and initial half-life of free INX-6295, resulting in a significant enhancement in tumor accumulation and improvement in tumor distribution of antisense oligodeoxynucleotides. Animals treated with SALP INX-6295 exhibited a prolonged reduction of c-myc expression, reduced tumor growth and increased mice survival. When administered in combination with cisplatin (DDP), SALP INX-6295 produced a complete tumor regression in approximately 30% of treated mice, which persisted for at least 60 days following the first cycle of treatment. Finally, the median survival of mice treated with DDP/SALP INX-6295 increased by 105% compared to 84% for animals treated with the combination DDP/free INX-6295. These data indicate that the biological activity and the therapeutic efficacy of c-myc antisense therapy may be improved when these agents are administered in lipid-based delivery systems.

  11. AP-2α Inhibits c-MYC Induced Oxidative Stress and Apoptosis in HaCaT Human Keratinocytes

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    Lei Yu

    2009-01-01

    AP-2 may have a direct effect on the c-myc gene. Chromatin immunoprecipitation assays demonstrated that AP-2 proteins bound to a cluster of AP-2 binding sites located within a 2 kb upstream regulatory region of c-myc These results suggest that the negative regulation of AP-2 on c-MYC activity was achieved through binding of AP-2 protein to the c-myc gene. The effects of AP-2 on c-MYC induced ROS accumulation and apoptosis in epidermal keratinocytes are likely to play an important role in cell growth, differentiation and carcinogenesis of the skin.

  12. Lanatoside C inhibits cell proliferation and induces apoptosis through attenuating Wnt/β-catenin/c-Myc signaling pathway in human gastric cancer cell.

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    Hu, Yudong; Yu, Kaikai; Wang, Gang; Zhang, Depeng; Shi, Chaoji; Ding, Yunhe; Hong, Duo; Zhang, Dan; He, Huiqiong; Sun, Lei; Zheng, Jun-Nian; Sun, Shuyang; Qian, Feng

    2018-04-01

    Gastric cancer is the third common cause of cancer mortality in the world with poor prognosis and high recurrence due to lack of effective medicines. Our studies revealed that lanatoside C, a FDA-approved cardiac glycoside, had an anti-proliferation effect on different human cancer cell lines (MKN-45; SGC-7901; HN4; MCF-7; HepG2) and gastric cell lines MKN-45 and SGC-7901 were the most sensitive cell lines to lanatoside C. MKN-45 cells treated with lanatoside C showed cell cycle arrest at G2/M phase and inhibition of cell migration. Meanwhile, upregulation of cleaved caspase-9 and cleaved PARP and downregulation of Bcl-xl were accompanied with the loss of mitochondrial membrane potential (MMP) and induction of intracellular reactive oxygen species (ROS). Lanatoside C inhibited Wnt/β-catenin signaling with downregulation of c-Myc, while overexpression of c-Myc reversed the anti-tumor effect of lanatoside C, confirming that c-Myc is a key drug target of lanatoside C. Furthermore, we discovered that lanatoside C prompted c-Myc degradation in proteasome-ubiquitin pathway with attenuating the binding of USP28 to c-Myc. These findings indicate that lanatoside C targeted c-Myc ubiquitination to inhibit MKN-45 proliferation and support the potential value of lanatoside C as a chemotherapeutic candidate. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Human RNA polymerase II associated factor 1 complex promotes tumorigenesis by activating c-MYC transcription in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Zhi, Xiuyi; Giroux-Leprieur, Etienne; Wislez, Marie; Hu, Mu; Zhang, Yi; Shi, Huaiyin; Du, Kaiqi; Wang, Lei

    2015-01-01

    Human RNA polymerase II (RNAPII)-associated factor 1 complex (hPAF1C) plays a crucial role in protein-coding gene transcription. Overexpression of hPAF1C has been implicated in the initiation and progression of various human cancers. However, the molecular pathways involved in tumorigenesis through hPAF1C remain to be elucidated. The current study suggested hPAF1C expression as a prognostic biomarker for early stage non-small cell lung cancer (NSCLC) and patients with low hPAF1C expression levels had significantly better overall survival. Furthermore, the expression of hPAF1C was found to be positively correlated with c-MYC expression in patient tumor samples and in cancer cell lines. Mechanistic studies indicated that hPAF1C could promote lung cancer cell proliferation through regulating c-MYC transcription. These results demonstrated the prognostic value of hPAF1C in early-stage NSCLC and the role of hPAF1C in the transcriptional regulation of c-MYC oncogene during NSCLC tumorigenesis. - Highlights: • hPAF1C expression is a prognostic biomarker for early stage non-small cell lung cancer. • The expression of hPAF1C was positively correlated with c-MYC in tumor samples of patients and in several NSCLC cell lines. • hPAF1C could promote lung cancer cell proliferation through regulating c-MYC transcription.

  14. High levels of stable p53 protein and the expression of c-myc in cultured human epithelial tissue after cobalt-60 irradiation

    International Nuclear Information System (INIS)

    Mothersill, C.; Seymour, C.B.; Harney, J.; Hennessy, T.P.

    1994-01-01

    When explants of human uroepithelium or esophageal epithelium are exposed to acute doses of radiation (cobalt-60), the cells which grow out to form the primary cultures show a number of abnormal features. These include the development of characteristic nonsenescent foci. These foci have previously been shown to be c-myc positive and to have an abnormal, tumor-like ultrastructure. Expression of c-myc and the level of stable p53 proteins have now been examined in these cultures 2 weeks after irradiation. Both proteins occurred in dividing cells at the growing edge of the explant and in the foci. The expression of c-myc appeared to be correlated with growth. As expected, variation between individual cultures of normal human cells was noted in the expression of stable p53 protein. Most control uroepithelial cell cultures were negative, but a small cohort showed a wide range of values. The control cultures from the esophageal tissues had high expression of p53, and this decreased marginally after irradiation. Cells positive for p53 were always in cycle and were usually positive for c-myc as well. It would appear from these results that the expression of c-myc and the stable form of the p53 protein occur in irradiated primary cultures of normal human cells both in foci which also express a number of abnormalities and in open-quotes edgeclose quotes cells which are dividing. Cultures of unirradiated cells from esophagus and a small number of uroepithelial samples had high levels of p53. Possible reasons for this are discussed. 33 refs., 2 figs., 3 tabs

  15. Multiple fractions of gamma rays do not induce overexpression of c-myc or c-Ki-ras oncogenes in human cervical carcinoma cells

    International Nuclear Information System (INIS)

    Osmak, M.; Soric, J.; Matulic, M.

    1993-01-01

    Multiple fractions of gamma rays (0.5 Gy daily, 30 fractions) had previously been found to change the sensitivity of human cervical carcinoma HeLa cells to anticancer drugs. Preirradiated cells became resistant to cisplatin, methotrexate and vincristine but retained the same sensitivity to gamma rays and ultraviolet light. Some mechanisms involved in the resistance of preirradiated cells to cisplatin and vincristine were determined, i.e. the increased levels of metallothioneins and increased expression of plasma membrane P glycoprotein. As recent reports indicated that the resistance to cisplatin and ionizing radiation may involve the expression of oncogenes, the problem was studied whether multiple fractions of gamma rays can change the expression of c-myc and c-Ki-ras oncogenes in HeLa cells and whether there is a correlation between the expression of these oncogenes and the sensitivity of preirradiated cells to cisplatin and gamma rays. The expression of c-myc and c-Ki-ras oncogenes was examined using the DNA dot blot, the RNA dot blot and Northern blot analysis. The results show that preirradiation induced neither amplification nor elevated expression of c-myc and c-Ki-ras oncogenes. Furthermore, there is no correlation between the expression of c-myc and c-Ki-ras oncogenes and the acquired resistance to cisplatin. (author) 3 figs., 32 refs

  16. The adaptive immune system promotes initiation of prostate carcinogenesis in a human c-Myc transgenic mouse model.

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    Melis, Monique H M; Nevedomskaya, Ekaterina; van Burgsteden, Johan; Cioni, Bianca; van Zeeburg, Hester J T; Song, Ji-Ying; Zevenhoven, John; Hawinkels, Lukas J A C; de Visser, Karin E; Bergman, Andries M

    2017-11-07

    Increasing evidence from epidemiological and pathological studies suggests a role of the immune system in the initiation and progression of multiple cancers, including prostate cancer. Reports on the contribution of the adaptive immune system are contradictive, since both suppression and acceleration of disease development have been reported. This study addresses the functional role of lymphocytes in prostate cancer development using a genetically engineered mouse model (GEMM) of human c-Myc driven prostate cancer (Hi-Myc mice) combined with B and T cell deficiency (RAG1 -/- mice). From a pre-cancerous stage on, Hi-Myc mice showed higher accumulation of immune cells in their prostates then wild-type mice, of which macrophages were the most abundant. The onset of invasive adenocarcinoma was delayed in Hi-MycRAG1 -/- compared to Hi-Myc mice and associated with decreased infiltration of leukocytes into the prostate. In addition, lower levels of the cytokines CXCL2, CCL5 and TGF-β1 were detected in Hi-MycRAG1 -/- compared to Hi-Myc mouse prostates. These results from a GEMM of prostate cancer provide new insights into the promoting role of the adaptive immune system in prostate cancer development. Our findings indicate that the endogenous adaptive immune system does not protect against de novo prostate carcinogenesis in Hi-Myc transgenic mice, but rather accelerates the formation of invasive adenocarcinomas. This may have implications for the development of novel treatment strategies.

  17. Effects of c-myc oncogene modulation on differentiation of human small cell lung carcinoma cell lines

    NARCIS (Netherlands)

    Van Waardenburg, RCAM; Meijer, C; Pinto-Sietsma, SJ; De Vries, EGE; Timens, W; Mulder, NM

    1998-01-01

    Amplification and over-expression of oncogenes of the myc family are related to the prognosis of certain solid tumors such as small cell lung cancer (SCLC). For SCLC, c-myc is the oncogene most consistently found to correlate with the end stage behaviour of the tumour, in particular with survival

  18. Somatostatin reduces 3H-thymidine incorporation and c-myc, but not thyroglobulin ribonucleic acid levels in human thyroid follicular cells in vitro

    International Nuclear Information System (INIS)

    degli Uberti, E.C.; Hanau, S.; Rossi, R.; Piva, R.; Margutti, A.; Trasforini, G.; Pansini, G.; del Senno, L.

    1991-01-01

    The action of somatostatin (SRIH) on 3 H-thymidine (thy) incorporation and on c-myc and thyroglobulin RNA levels in a suspension of follicles from normal and goitrous human thyroid was examined. SRIH, at 10 - 7 M concentration, inhibited basal thy incorporation (maximally by 4 h lasting for up 24 h), which effect was greater in goiter than in normal thyroid and was also detected in growing adherent epithelial cells. Moreover, in a follicle suspension SRIH prevented TSH-stimulated thy incorporation, both in normal and in goitrous thyroid. Basal expression of c-myc RNA was not affected by SRIH in either tissue, whereas the TSH-stimulated c-myc RNA level was significantly reduced in goiter. No effect of SRIH was observed on basal or TSH-stimulated thyroglobulin RNA levels. SRIH did not alter basal cAMP concentrations in normal or goitrous follicles, but it significantly reduced TSH-stimulated cAMP accumulation both in normal thyroid and in goiter. Overall, our data indicate a direct inhibitory action of SRIH on growth, but not on differentiation, of human thyroid, probably by a mechanism not entirely cAMP dependent

  19. Human amniotic epithelial cell feeder layers maintain mouse embryonic stem cell pluripotency via epigenetic regulation of the c-Myc promoter.

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    Liu, Te; Cheng, Weiwei; Liu, Tianjin; Guo, Lihe; Huang, Qin; Jiang, Lizhen; Du, Xiling; Xu, Fuhui; Liu, Zhixue; Lai, Dongmei

    2010-02-01

    Mouse embryonic stem cells (ESCs) are typically cultured on a feeder layer of mouse embryonic fibroblasts (MEFs), with leukemia inhibitory factor (LIF) added to maintain them in an undifferentiated state. We have previously shown that human amniotic epithelial cells (hAECs) can be used as feeder cells to maintain mouse ESC pluripotency, but the mechanism for this is unknown. In the present study, we found that CpG islands 5' of the c-Myc gene remain hypomethylated in mouse ESCs cultured on hAECs. In addition, levels of acetylation of histone H3 and trimethylation of histone H3K4 in the c-Myc gene promoter were higher in ES cells cultured on hAECs than those in ES cells cultured on MEFs. These data suggested that hAECs can alter mouse ESC gene expression via epigenetic modification of c-Myc, providing a possible mechanism for the hAEC-induced maintenance of ESCs in an undifferentiated state.

  20. Mechanism of estrogen activation of c-myc oncogene expression.

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    Dubik, D; Shiu, R P

    1992-08-01

    The estrogen receptor complex is a known trans-acting factor that regulates transcription of specific genes through an interaction with a specific estrogen-responsive cis-acting element (ERE). In previous studies we have shown that in estrogen-responsive human breast cancer cells estrogen rapidly activates c-myc expression. This activated expression occurs through enhanced transcription and does not require the synthesis of new protein intermediates; therefore, an ERE is present in the human c-myc gene regulatory region. To localize the ERE, constructs containing varying lengths of the c-myc 5'-flanking region ranging from -2327 to +25 (relative to the P1 promoter) placed adjacent to the chloramphenicol acetyl transferase reporter gene (CAT) were prepared. They were used in transient transfection studies in MCF-7 and HeLa cells co-transfected with an estrogen receptor expression vector. These studies reveal that all constructs containing the P2 promoter region exhibited estrogen-regulated CAT expression and that a 116-bp region upstream and encompassing the P2 TATA box is necessary for this activity. Analysis of this 116-bp region failed to identify a cis-acting element with sequences resembling the consensus ERE; however, co-transfection studies with mutant estrogen receptor expression vectors showed that the DNA-binding domain of the receptor is essential for estrogen-regulated CAT gene expression. We have also observed that anti-estrogen receptor complexes can weakly trans-activate from this 116-bp region but fail to do so from the ERE-containing ApoVLDLII-CAT construct. To explain these results we propose a new mechanism of estrogen trans-activation in the c-myc gene promoter.

  1. The c-Myc target glycoprotein1balpha links cytokinesis failure to oncogenic signal transduction pathways in cultured human cells.

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    Qian Wu

    2010-05-01

    Full Text Available An increase in chromosome number, or polyploidization, is associated with a variety of biological changes including breeding of cereal crops and flowers, terminal differentiation of specialized cells such as megakaryocytes, cellular stress and oncogenic transformation. Yet it remains unclear how cells tolerate the major changes in gene expression, chromatin organization and chromosome segregation that invariably accompany polyploidization. We show here that cancer cells can initiate increases in chromosome number by inhibiting cell division through activation of glycoprotein1b alpha (GpIbalpha, a component of the c-Myc signaling pathway. We are able to recapitulate cytokinesis failure in primary cells by overexpression of GpIbalpha in a p53-deficient background. GpIbalpha was found to localize to the cleavage furrow by microscopy analysis and, when overexpressed, to interfere with assembly of the cellular cortical contraction apparatus and normal division. These results indicate that cytokinesis failure and tetraploidy in cancer cells are directly linked to cellular hyperproliferation via c-Myc induced overexpression of GpIbalpha.

  2. Ezrin mediates c-Myc actions in prostate cancer cell invasion

    DEFF Research Database (Denmark)

    Chuan, Yin Choy; Iglesias Gato, Diego; Fernandez-Perez, L

    2010-01-01

    The forced overexpression of c-Myc in mouse prostate and in normal human prostate epithelial cells results in tumor transformation with an invasive phenotype. How c-Myc regulates cell invasion is poorly understood. In this study, we have investigated the interplay of c-Myc and androgens in the re...

  3. Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30{sup II} accessory protein and the induction of oncogenic cellular transformation by p30{sup II}/c-MYC

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    Romeo, Megan M.; Ko, Bookyung; Kim, Janice; Brady, Rebecca; Heatley, Hayley C.; He, Jeffrey; Harrod, Carolyn K.; Barnett, Braden [Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275-0376 (United States); Ratner, Lee [Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Lairmore, Michael D. [University of California-Davis, School of Veterinary Medicine, One Shields Avenue, Davis, CA 95618 (United States); Martinez, Ernest [Department of Biochemistry, University of California, Riverside, CA 92521 (United States); Lüscher, Bernhard [Institute of Biochemistry, Klinikum, RWTH Aachen University, Pauwelsstrasse 30, 52057 Aachen (Germany); Robson, Craig N. [Northern Institute for Cancer Research, Newcastle University, The Medical School, Newcastle upon Tyne, NE2 4HH (United Kingdom); Henriksson, Marie [Department of Microbiology, Cell and Tumor Biology, Karolinska Institutet, Stockholm (Sweden); Harrod, Robert, E-mail: rharrod@smu.edu [Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275-0376 (United States)

    2015-02-15

    The human T-cell leukemia retrovirus type-1 (HTLV-1) p30{sup II} protein is a multifunctional latency-maintenance factor that negatively regulates viral gene expression and deregulates host signaling pathways involved in aberrant T-cell growth and proliferation. We have previously demonstrated that p30{sup II} interacts with the c-MYC oncoprotein and enhances c-MYC-dependent transcriptional and oncogenic functions. However, the molecular and biochemical events that mediate the cooperation between p30{sup II} and c-MYC remain to be completely understood. Herein we demonstrate that p30{sup II} induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys→Arg substitution mutants are impaired for oncogenic transformation with p30{sup II} in c-myc{sup −/−} HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30{sup II} is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30{sup II} inhibits apoptosis in proliferating cells expressing c-MYC under conditions of genotoxic stress. These findings suggest that c-MYC-acetylation is required for the cooperation between p30{sup II}/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. - Highlights: • Acetylation of c-MYC is required for oncogenic transformation by HTLV-1 p30{sup II}/c-MYC. • Acetylation-defective c-MYC mutants are impaired for foci-formation by p30{sup II}/c-MYC. • The HTLV-1 p30{sup II} protein induces lysine-acetylation of c-MYC. • p30{sup II} is present in c-MYC nucleoprotein complexes in HTLV-1-transformed T-cells. • HTLV-1 p30{sup II} inhibits apoptosis in c-MYC-expressing proliferating cells.

  4. The human thyroglobulin gene: a polymorphic marker localized distal to C-MYC on chromosome 8 band q24

    NARCIS (Netherlands)

    Baas, F.; Bikker, H.; Geurts van Kessel, A.; Melsert, R.; Pearson, P. L.; de Vijlder, J. J.; van Ommen, G. J.

    1985-01-01

    The human thyroglobulin (Tg) gene is localized to chromosome 8 and regionally to band q24 as shown independently by both in situ hybridization techniques and Southern blot analysis of human-rodent somatic cell hybrids. Analysis of hybrids derived from a Burkitt lymphoma, with a translocation

  5. Mechanisms of c-myc degradation by nickel compounds and hypoxia.

    Directory of Open Access Journals (Sweden)

    Qin Li

    2009-12-01

    Full Text Available Nickel (Ni compounds have been found to cause cancer in humans and animal models and to transform cells in culture. At least part of this effect is mediated by stabilization of hypoxia inducible factor (HIF1a and activating its downstream signaling. Recent studies reported that hypoxia signaling might either antagonize or enhance c-myc activity depending on cell context. We investigated the effect of nickel on c-myc levels, and demonstrated that nickel, hypoxia, and other hypoxia mimetics degraded c-myc protein in a number of cancer cells (A549, MCF-7, MDA-453, and BT-474. The degradation of the c-Myc protein was mediated by the 26S proteosome. Interestingly, knockdown of both HIF-1alpha and HIF-2alpha attenuated c-Myc degradation induced by Nickel and hypoxia, suggesting the functional HIF-1alpha and HIF-2alpha was required for c-myc degradation. Further studies revealed two potential pathways mediated nickel and hypoxia induced c-myc degradation. Phosphorylation of c-myc at T58 was significantly increased in cells exposed to nickel or hypoxia, leading to increased ubiquitination through Fbw7 ubiquitin ligase. In addition, nickel and hypoxia exposure decreased USP28, a c-myc de-ubiquitinating enzyme, contributing to a higher steady state level of c-myc ubiquitination and promoting c-myc degradation. Furthermore, the reduction of USP28 protein by hypoxia signaling is due to both protein degradation and transcriptional repression. Nickel and hypoxia exposure significantly increased the levels of dimethylated H3 lysine 9 at the USP28 promoter and repressed its expression. Our study demonstrated that Nickel and hypoxia exposure increased c-myc T58 phosphorylation and decreased USP28 protein levels in cancer cells, which both lead to enhanced c-myc ubiquitination and proteasomal degradation.

  6. Genomic amplification patterns of human telomerase RNA gene and C-MYC in liquid-based cytological specimens used for the detection of high-grade cervical intraepithelial neoplasia

    Directory of Open Access Journals (Sweden)

    Chen Shaomin

    2012-04-01

    Full Text Available Abstract Background The amplification of oncogenes initiated by high-risk human papillomavirus (HPV infection is an early event in cervical carcinogenesis and can be used for cervical lesion diagnosis. We measured the genomic amplification rates and the patterns of human telomerase RNA gene (TERC and C-MYC in the liquid-based cytological specimens to evaluate the diagnostic characteristics for the detection of high-grade cervical lesions. Methods Two hundred and forty-three residual cytological specimens were obtained from outpatients aged 25 to 64 years at Qilu Hospital, Shandong University. The specimens were evaluated by fluorescence in situ hybridization (FISH using chromosome probes to TERC (3q26 and C-MYC (8q24. All of the patients underwent colposcopic examination and histological evaluation. A Chi-square test was used for categorical data analysis. Results In the normal, cervical intraepithelial neoplasia grade 1 (CIN1, grade 2 (CIN2, grade 3 (CIN3 and squamous cervical cancer (SCC cases, the TERC positive rates were 9.2%, 17.2%, 76.2%, 100.0% and 100.0%, respectively; the C-MYC positive rates were 20.7%, 31.0%, 71.4%, 81.8% and 100.0%, respectively. The TERC and C-MYC positive rates were higher in the CIN2+ (CIN2, CIN3 and SCC cases than in the normal and CIN1 cases (p p p > 0.05. Conclusions The TERC test is highly sensitive and is therefore suitable for cervical cancer screening. The C-MYC test is not suitable for cancer screening because of its lower sensitivity. The amplification patterns of TERC become more diverse and complex as the severity of cervical diseases increases, whereas for C-MYC, the amplification patterns are similar between the normal/CIN1 and CIN2+ groups. Virtual slides The virtual slide(s for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1308004512669913.

  7. AMPK promotes survival of c-Myc-positive melanoma cells by suppressing oxidative stress.

    Science.gov (United States)

    Kfoury, Alain; Armaro, Marzia; Collodet, Caterina; Sordet-Dessimoz, Jessica; Giner, Maria Pilar; Christen, Stefan; Moco, Sofia; Leleu, Marion; de Leval, Laurence; Koch, Ute; Trumpp, Andreas; Sakamoto, Kei; Beermann, Friedrich; Radtke, Freddy

    2018-03-01

    Although c-Myc is essential for melanocyte development, its role in cutaneous melanoma, the most aggressive skin cancer, is only partly understood. Here we used the Nras Q61K INK4a -/- mouse melanoma model to show that c-Myc is essential for tumor initiation, maintenance, and metastasis. c-Myc-expressing melanoma cells were preferentially found at metastatic sites, correlated with increased tumor aggressiveness and high tumor initiation potential. Abrogation of c-Myc caused apoptosis in primary murine and human melanoma cells. Mechanistically, c-Myc-positive melanoma cells activated and became dependent on the metabolic energy sensor AMP-activated protein kinase (AMPK), a metabolic checkpoint kinase that plays an important role in energy and redox homeostasis under stress conditions. AMPK pathway inhibition caused apoptosis of c-Myc-expressing melanoma cells, while AMPK activation protected against cell death of c-Myc-depleted melanoma cells through suppression of oxidative stress. Furthermore, TCGA database analysis of early-stage human melanoma samples revealed an inverse correlation between C-MYC and patient survival, suggesting that C-MYC expression levels could serve as a prognostic marker for early-stage disease. © 2018 The Authors.

  8. Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaojing [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Xu, Yonghong [Institute of Ophthalmological Research, Department of Ophthalmology, Renmin Hospital of Wuhan University, 430060 Wuhan (China); Meng, Xiangning [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Watari, Fumio [Department of Biomedical, Dental Materials and Engineering, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586 (Japan); Liu, Hudan, E-mail: hudanliu@hust.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China); Chen, Xiao, E-mail: mornsmile@yahoo.com [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan (China)

    2015-01-01

    Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABC gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.

  9. Targeting human c-Myc promoter duplex DNA with actinomycin D by use of multi-way analysis of quantum-dot-mediated fluorescence resonance energy transfer

    DEFF Research Database (Denmark)

    Gholami, Somayeh; Kompany Zare, Mohsen

    2013-01-01

    Actinomycin D (Act D), an oncogenic c-Myc promoter binder, interferes with the action of RNA polymerase. There is great demand for high-throughput technology able to monitor the activity of DNA-binding drugs. To this end, binding of 7-aminoactinomycin D (7AAD) to the duplex c-Myc promoter...... pairs resulted in efficient energy transfer from drug to QD via fluorescence resonance energy transfer (FRET). Multi-way analysis of the three-way data array obtained from titration experiments was performed by use of restricted Tucker3 and hard trilinear decomposition (HTD). These techniques enable...... the important advantage over univariate classical methods of enabling us to investigate the source of variance in the fluorescence signal of the DNA-drug complex. It was established that hard trilinear decomposition analysis of FRET-measured data overcomes the problem of rank deficiency, enabling calculation...

  10. c-myc Amplification Is Frequent in Esophageal Adenocarcinoma and Correlated with the Upregulation of VEGF-A Expression

    Directory of Open Access Journals (Sweden)

    Burkhard H.A. von Rahden

    2006-09-01

    Full Text Available BACKGROUND: Deregulation of c-myc plays a major role in the carcinogenesis of human malignancies. We investigated the amplification of the c-myc gene in a surgical series of Barrett cancers. METHODS: Primary resected esophageal (Barrett adenocarcinomas (n = 84 were investigated for c-myc amplification using chromogene in situ hybridization. Tumor samples were assembled in a tissue microarray. c-myc gene dosage was correlated with clinicopathologic parameters, including the survival and gene expression of cyclooxygenases (COX-1 and COX-2 and proangiogenic growth factors (VEGF-A and VEGF-C. RESULTS: The majority (70 of 84; 83.3% exhibited amplification of the c-myc gene. There were low-level amplifications in 63 (75.0% cases and high-level amplifications in 7 (8.3% cases. No amplification was found in 14 (16.7% cases. Tumors without c-myc amplification had lower VEGF-A, VEGF-C, and COX-2 expression levels than tumors with low-level and high-level c-myc amplification (statistically significant for VEGF-A; P = .0348. c-myc amplification was not correlated with clinicopathological parameters or survival. Only diffuse and mixed-type tumors, according to Lauren classification, exhibited c-myc amplifications more frequently (P = .0466. CONCLUSIONS: Amplifications of the c-myc gene are frequent in Barrett cancer. c-myc may be involved in the regulation of angiogenesis.

  11. c-Myc activates BRCA1 gene expression through distal promoter elements in breast cancer cells

    International Nuclear Information System (INIS)

    Chen, Yinghua; Xu, Jinhua; Borowicz, Stanley; Collins, Cindy; Huo, Dezheng; Olopade, Olufunmilayo I

    2011-01-01

    The BRCA1 gene plays an important role in the maintenance of genomic stability. BRCA1 inactivation contributes to breast cancer tumorigenesis. An increasing number of transcription factors have been shown to regulate BRCA1 expression. c-Myc can act as a transcriptional activator, regulating up to 15% of all genes in the human genome and results from a high throughput screen suggest that BRCA1 is one of its targets. In this report, we used cultured breast cancer cells to examine the mechanisms of transcriptional activation of BRCA1 by c-Myc. c-Myc was depleted using c-Myc-specific siRNAs in cultured breast cancer cells. BRCA1 mRNA expression and BRCA1 protein expression were determined by quantitative RT-PCR and western blot, respectively and BRCA1 promoter activities were examined under these conditions. DNA sequence analysis was conducted to search for high similarity to E boxes in the BRCA1 promoter region. The association of c-Myc with the BRCA1 promoter in vivo was tested by a chromatin immunoprecipitation assay. We investigated the function of the c-Myc binding site in the BRCA1 promoter region by a promoter assay with nucleotide substitutions in the putative E boxes. BRCA1-dependent DNA repair activities were measured by a GFP-reporter assay. Depletion of c-Myc was found to be correlated with reduced expression levels of BRCA1 mRNA and BRCA1 protein. Depletion of c-Myc decreased BRCA1 promoter activity, while ectopically expressed c-Myc increased BRCA1 promoter activity. In the distal BRCA1 promoter, DNA sequence analysis revealed two tandem clusters with high similarity, and each cluster contained a possible c-Myc binding site. c-Myc bound to these regions in vivo. Nucleotide substitutions in the c-Myc binding sites in these regions abrogated c-Myc-dependent promoter activation. Furthermore, breast cancer cells with reduced BRCA1 expression due to depletion of c-Myc exhibited impaired DNA repair activity. The distal BRCA1 promoter region is associated with c-Myc

  12. Clinicopathological significance of c-MYC in esophageal squamous cell carcinoma.

    Science.gov (United States)

    Lian, Yu; Niu, Xiangdong; Cai, Hui; Yang, Xiaojun; Ma, Haizhong; Ma, Shixun; Zhang, Yupeng; Chen, Yifeng

    2017-07-01

    Esophageal squamous cell carcinoma is one of the most common malignant tumors. The oncogene c-MYC is thought to be important in the initiation, promotion, and therapy resistance of cancer. In this study, we aim to investigate the clinicopathologic roles of c-MYC in esophageal squamous cell carcinoma tissue. This study is aimed at discovering and analyzing c-MYC expression in a series of human esophageal tissues. A total of 95 esophageal squamous cell carcinoma samples were analyzed by the western blotting and immunohistochemistry techniques. Then, correlation of c-MYC expression with clinicopathological features of esophageal squamous cell carcinoma patients was statistically analyzed. In most esophageal squamous cell carcinoma cases, the c-MYC expression was positive in tumor tissues. The positive rate of c-MYC expression in tumor tissues was 61.05%, obviously higher than the adjacent normal tissues (8.42%, 8/92) and atypical hyperplasia tissues (19.75%, 16/95). There was a statistical difference among adjacent normal tissues, atypical hyperplasia tissues, and tumor tissues. Overexpression of the c-MYC was detected in 61.05% (58/95) esophageal squamous cell carcinomas, which was significantly correlated with the degree of differentiation (p = 0.004). The positive rate of c-MYC expression was 40.0% in well-differentiated esophageal tissues, with a significantly statistical difference (p = 0.004). The positive rate of c-MYC was 41.5% in T1 + T2 esophageal tissues and 74.1% in T3 + T4 esophageal tissues, with a significantly statistical difference (p = 0.001). The positive rate of c-MYC was 45.0% in I + II esophageal tissues and 72.2% in III + IV esophageal tissues, with a significantly statistical difference (p = 0.011). The c-MYC expression strongly correlated with clinical staging (p = 0.011), differentiation degree (p = 0.004), lymph node metastasis (p = 0.003), and invasion depth (p = 0.001) of patients with esophageal squamous cell carcinoma. The c-MYC was

  13. c-Myc is essential to prevent endothelial pro-inflammatory senescent phenotype.

    Directory of Open Access Journals (Sweden)

    Victoria Florea

    Full Text Available The proto-oncogene c-Myc is vital for vascular development and promotes tumor angiogenesis, but the mechanisms by which it controls blood vessel growth remain unclear. In the present work we investigated the effects of c-Myc knockdown in endothelial cell functions essential for angiogenesis to define its role in the vasculature. We provide the first evidence that reduction in c-Myc expression in endothelial cells leads to a pro-inflammatory senescent phenotype, features typically observed during vascular aging and pathologies associated with endothelial dysfunction. c-Myc knockdown in human umbilical vein endothelial cells using lentivirus expressing specific anti-c-Myc shRNA reduced proliferation and tube formation. These functional defects were associated with morphological changes, increase in senescence-associated-β-galactosidase activity, upregulation of cell cycle inhibitors and accumulation of c-Myc-deficient cells in G1-phase, indicating that c-Myc knockdown in endothelial cells induces senescence. Gene expression analysis of c-Myc-deficient endothelial cells showed that senescent phenotype was accompanied by significant upregulation of growth factors, adhesion molecules, extracellular-matrix components and remodeling proteins, and a cluster of pro-inflammatory mediators, which include Angptl4, Cxcl12, Mdk, Tgfb2 and Tnfsf15. At the peak of expression of these cytokines, transcription factors known to be involved in growth control (E2f1, Id1 and Myb were downregulated, while those involved in inflammatory responses (RelB, Stat1, Stat2 and Stat4 were upregulated. Our results demonstrate a novel role for c-Myc in the prevention of vascular pro-inflammatory phenotype, supporting an important physiological function as a central regulator of inflammation and endothelial dysfunction.

  14. Evaluation of Molecular Inhibitors of the c-Myc Oncoprotein

    National Research Council Canada - National Science Library

    Prochownik, Edward V

    2005-01-01

    .... All of these functions require that C-Myc physically associate with another protein. Max. Example of diseases in which c-Myc deregulation occurs include breast cancer (approx. 30% of cases), colon cancer (>85...

  15. Shikonin regulates C-MYC and GLUT1 expression through the MST1-YAP1-TEAD1 axis

    Energy Technology Data Exchange (ETDEWEB)

    Vališ, Karel, E-mail: karel.valis@biomed.cas.cz [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic); Talacko, Pavel; Grobárová, Valéria [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic); Černý, Jan [Faculty of Science, Charles University, Prague (Czech Republic); Novák, Petr, E-mail: pnovak@biomed.cas.cz [Laboratory of Structural Biology and Cell Signaling, Institute of Microbiology, v.v.i., The Czech Academy of Sciences, Prague (Czech Republic); Faculty of Science, Charles University, Prague (Czech Republic)

    2016-12-10

    The general mechanism underlying the tumor suppressor activity of the Hippo signaling pathway remains unclear. In this study, we explore the molecular mechanisms connecting the Hippo signaling pathway with glucose metabolism. We have found that two key regulators of glycolysis, C-MYC and GLUT1, are targets of the Hippo signaling pathway in human leukemia cells. Our results revealed that activation of MST1 by the natural compound shikonin inhibited the expression of GLUT1 and C-MYC. Furthermore, RNAi experiments confirmed the regulation of GLUT1 and C-MYC expression via the MST1-YAP1-TEAD1 axis. Surprisingly, YAP1 was found to positively regulate C-MYC mRNA levels in complex with TEAD1, while it negatively regulates C-MYC levels in cooperation with MST1. Hence, YAP1 serves as a rheostat for C-MYC, which is regulated by MST1. In addition, depletion of MST1 stimulates lactate production, whereas the specific depletion of TEAD1 has an opposite effect. The inhibition of lactate production and cellular proliferation induced by shikonin also depends on the Hippo pathway activity. Finally, a bioinformatic analysis revealed conserved TEAD-binding motifs in the C-MYC and GLUT1 promoters providing another molecular data supporting our observations. In summary, regulation of glucose metabolism could serve as a new tumor suppressor mechanism orchestrated by the Hippo signaling pathway. - Highlights: • Shikonin inhibits C-MYC and GLUT1 expression in MST1 and YAP1 dependent manner. • YAP1-TEAD1 interaction activates C-MYC and GLUT1 expression. • MST1 in cooperation with YAP1 inhibits C-MYC and GLUT1 expression. • MST1-YAP1-TEAD1 axis regulates lactate production by leukemic cells. • MST1 and YAP1 proteins block proliferation of leukemic cells.

  16. The 5T mouse multiple myeloma model: Absence of c-myc oncogene rearrangement in early transplant generations

    NARCIS (Netherlands)

    Radl, J.; Punt, Y.A.; Enden-Vieveen, M.H.M. van den; Bentvelzen, P.A.J.; Bakkus, M.H.C.; Akker T., W. van den; Benner, R.

    1990-01-01

    Consistent chromosomal translocations involving the c-myc cellular oncogene and one of the three immunoglobulin loci are typical for human Burkitt's lymphoma, induced mouse plasmacytoma (MPC) and spontaneously arising rat immunocytoma (RIC). Another plasma cell malignancy, multiple myeloma (MM),

  17. Fluorescent Dansyl-Guanosine Conjugates that Bind c-MYC Promoter G-Quadruplex and Downregulate c-MYC Expression.

    Science.gov (United States)

    Pavan Kumar, Y; Saha, Puja; Saha, Dhurjhoti; Bessi, Irene; Schwalbe, Harald; Chowdhury, Shantanu; Dash, Jyotirmayee

    2016-03-02

    The four-stranded G-quadruplex present in the c-MYC P1 promoter has been shown to play a pivotal role in the regulation of c-MYC transcription. Small-molecule compounds capable of inhibiting the c-MYC promoter activity by stabilising the c-MYC G-quadruplex could potentially be used as anticancer agents. In this context, here we report the synthesis of dansyl-guanosine conjugates through one-pot modular click reactions. The dansyl-guanosine conjugates can selectively detect c-MYC G-quadruplex over other biologically relevant quadruplexes and duplex DNA and can be useful as staining reagents for selective visualisation of c-MYC G-quadruplex over duplex DNA by gel electrophoresis. NMR spectroscopic titrations revealed the preferential binding sites of these dansyl ligands to the c-MYC G-quadruplex. A dual luciferase assay and qRT-PCR revealed that a dansyl-bisguanosine ligand represses the c-MYC expression, possibly by stabilising the c-MYC G-quadruplex. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. c-myc overexpression causes anaplasia in medulloblastoma.

    Science.gov (United States)

    Stearns, Duncan; Chaudhry, Aneeka; Abel, Ty W; Burger, Peter C; Dang, Chi V; Eberhart, Charles G

    2006-01-15

    Both anaplasia and increased c-myc gene expression have been shown to be negative prognostic indicators for survival in medulloblastoma patients. myc gene amplification has been identified in many large cell/anaplastic medulloblastoma, but no causative link between c-myc and anaplastic changes has been established. To address this, we stably overexpressed c-myc in two medulloblastoma cell lines, DAOY and UW228, and examined the changes in growth characteristics. When analyzed in vitro, cell lines with increased levels of c-myc had higher rates of growth and apoptosis as well as significantly improved ability to form colonies in soft agar compared with control. When injected s.c. into nu/nu mice, flank xenograft tumors with high levels of c-myc in DAOY cell line background were 75% larger than those derived from control. Overexpression of c-myc was required for tumor formation by UW228 cells. Most remarkably, the histopathology of the Myc tumors was severely anaplastic, with large areas of necrosis/apoptosis, increased nuclear size, and macronucleoli. Indices of proliferation and apoptosis were also significantly higher in Myc xenografts. Thus, c-myc seems to play a causal role in inducing anaplasia in medulloblastoma. Because anaplastic changes are often observed in recurrent medulloblastoma, we propose that c-myc dysregulation is involved in the progression of these malignant embryonal neoplasms.

  19. RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells

    International Nuclear Information System (INIS)

    Bueren, André O von; Shalaby, Tarek; Oehler-Jänne, Christoph; Arnold, Lucia; Stearns, Duncan; Eberhart, Charles G; Arcaro, Alexandre; Pruschy, Martin; Grotzer, Michael A

    2009-01-01

    With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA) and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR) and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425). siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT) expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly

  20. RNA interference-mediated c-MYC inhibition prevents cell growth and decreases sensitivity to radio- and chemotherapy in childhood medulloblastoma cells

    Directory of Open Access Journals (Sweden)

    Arcaro Alexandre

    2009-01-01

    Full Text Available Abstract Background With current treatment strategies, nearly half of all medulloblastoma (MB patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to cause anaplasia and correlate with unfavorable prognosis. Methods To study the role of c-MYC in MB biology, we down-regulated c-MYC expression by using small interfering RNA (siRNA and investigated changes in cellular proliferation, cell cycle analysis, apoptosis, telomere maintenance, and response to ionizing radiation (IR and chemotherapeutics in a representative panel of human MB cell lines expressing different levels of c-MYC (DAOY wild-type, DAOY transfected with the empty vector, DAOY transfected with c-MYC, D341, and D425. Results siRNA-mediated c-MYC down-regulation resulted in an inhibition of cellular proliferation and clonogenic growth, inhibition of G1-S phase cell cycle progression, and a decrease in human telomerase reverse transcriptase (hTERT expression and telomerase activity. On the other hand, down-regulation of c-MYC reduced apoptosis and decreased the sensitivity of human MB cells to IR, cisplatin, and etoposide. This effect was more pronounced in DAOY cells expressing high levels of c-MYC when compared with DAOY wild-type or DAOY cells transfected with the empty vector. Conclusion In human MB cells, in addition to its roles in growth and proliferation, c-MYC is also a potent inducer of apoptosis. Therefore, targeting c-MYC might be of therapeutic benefit when used sequentially with chemo- and radiotherapy rather than concomitantly.

  1. Genetic and genomic analysis modeling of germline c-MYC overexpression and cancer susceptibility

    Directory of Open Access Journals (Sweden)

    Nunes Virginia

    2008-01-01

    Full Text Available Abstract Background Germline genetic variation is associated with the differential expression of many human genes. The phenotypic effects of this type of variation may be important when considering susceptibility to common genetic diseases. Three regions at 8q24 have recently been identified to independently confer risk of prostate cancer. Variation at 8q24 has also recently been associated with risk of breast and colorectal cancer. However, none of the risk variants map at or relatively close to known genes, with c-MYC mapping a few hundred kilobases distally. Results This study identifies cis-regulators of germline c-MYC expression in immortalized lymphocytes of HapMap individuals. Quantitative analysis of c-MYC expression in normal prostate tissues suggests an association between overexpression and variants in Region 1 of prostate cancer risk. Somatic c-MYC overexpression correlates with prostate cancer progression and more aggressive tumor forms, which was also a pathological variable associated with Region 1. Expression profiling analysis and modeling of transcriptional regulatory networks predicts a functional association between MYC and the prostate tumor suppressor KLF6. Analysis of MYC/Myc-driven cell transformation and tumorigenesis substantiates a model in which MYC overexpression promotes transformation by down-regulating KLF6. In this model, a feedback loop through E-cadherin down-regulation causes further transactivation of c-MYC. Conclusion This study proposes that variation at putative 8q24 cis-regulator(s of transcription can significantly alter germline c-MYC expression levels and, thus, contribute to prostate cancer susceptibility by down-regulating the prostate tumor suppressor KLF6 gene.

  2. c-MYC expression sensitizes medulloblastoma cells to radio- and chemotherapy and has no impact on response in medulloblastoma patients

    Directory of Open Access Journals (Sweden)

    Stearns Duncan

    2011-02-01

    Full Text Available Abstract Background To study whether and how c-MYC expression determines response to radio- and chemotherapy in childhood medulloblastoma (MB. Methods We used DAOY and UW228 human MB cells engineered to stably express different levels of c-MYC, and tested whether c-MYC expression has an effect on radio- and chemosensitivity using the colorimetric 3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium inner salt (MTS assay, clonogenic survival, apoptosis assays, cell cycle analysis, and western blot assessment. In an effort to validate our results, we analyzed c-MYC mRNA expression in formalin-fixed paraffin-embedded tumor samples from well-documented patients with postoperative residual tumor and compared c-MYC mRNA expression with response to radio- and chemotherapy as examined by neuroradiological imaging. Results In DAOY - and to a lesser extent in UW228 - cells expressing high levels of c-MYC, the cytotoxicity of cisplatin, and etoposide was significantly higher when compared with DAOY/UW228 cells expressing low levels of c-MYC. Irradiation- and chemotherapy-induced apoptotic cell death was enhanced in DAOY cells expressing high levels of c-MYC. The response of 62 of 66 residual tumors was evaluable and response to postoperative radio- (14 responders (CR, PR vs. 5 non-responders (SD, PD or chemotherapy (23 CR/PR vs. 20 SD/PD was assessed. c-MYC mRNA expression was similar in primary MB samples of responders and non-responders (Mann-Whitney U test, p = 0.50, ratio 0.49, 95% CI 0.008-30.0 and p = 0.67, ratio 1.8, 95% CI 0.14-23.5, respectively. Conclusions c-MYC sensitizes MB cells to some anti-cancer treatments in vitro. As we failed to show evidence for such an effect on postoperative residual tumors when analyzed by imaging, additional investigations in xenografts and larger MB cohorts may help to define the exact function of c-MYC in modulating response to treatment.

  3. Disruption of MEK/ERK/c-Myc signaling radiosensitizes prostate cancer cells in vitro and in vivo.

    Science.gov (United States)

    Ciccarelli, Carmela; Di Rocco, Agnese; Gravina, Giovanni Luca; Mauro, Annunziata; Festuccia, Claudio; Del Fattore, Andrea; Berardinelli, Paolo; De Felice, Francesca; Musio, Daniela; Bouché, Marina; Tombolini, Vincenzo; Zani, Bianca Maria; Marampon, Francesco

    2018-06-29

    Prostate cancer (PCa) cell radioresistance causes the failure of radiation therapy (RT) in localized or locally advanced disease. The aberrant accumulation of c-Myc oncoprotein, known to promote PCa onset and progression, may be due to the control of gene transcription and/or MEK/ERK-regulated protein stabilization. Here, we investigated the role of MEK/ERK signaling in PCa. LnCAP, 22Rv1, DU145, and PC3 PCa cell lines were used in in vitro and in vivo experiments. U0126, trametinib MEK/ERK inhibitors, and c-Myc shRNAs were used. Radiation was delivered using an x-6 MV photon linear accelerator. U0126 in vivo activity alone or in combination with irradiation was determined in murine xenografts. Inhibition of MEK/ERK signaling down-regulated c-Myc protein in PCa cell lines to varying extents by affecting expression of RNA and protein, which in turn determined radiosensitization in in vitro and in vivo xenograft models of PCa cells. The crucial role played by c-Myc in the MEK/ERK pathways was demonstrated in 22Rv1 cells by the silencing of c-Myc by means of short hairpin mRNA, which yielded effects resembling the targeting of MEK/ERK signaling. The clinically approved compound trametinib used in vitro yielded the same effects as U0126 on growth and C-Myc expression. Notably, U0126 and trametinib induced a drastic down-regulation of BMX, which is known to prevent apoptosis in cancer cells. The results of our study suggest that signal transduction-based therapy can, by disrupting the MEK/ERK/c-Myc axis, reduce human PCa radioresistance caused by increased c-Myc expression in vivo and in vitro and restores apoptosis signals.

  4. Targeting c-Myc: JQ1 as a promising option for c-Myc-amplified esophageal squamous cell carcinoma.

    Science.gov (United States)

    Wang, Jingyuan; Liu, Zhentao; Wang, Ziqi; Wang, Shubin; Chen, Zuhua; Li, Zhongwu; Zhang, Mengqi; Zou, Jianling; Dong, Bin; Gao, Jing; Shen, Lin

    2018-04-10

    c-Myc amplification-induced cell cycle dysregulation is a common cause for esophageal squamous cell carcinoma (ESCC), but no approved targeted drug is available so far. The bromodomain inhibitor JQ1, which targets c-Myc, exerts anti-tumor activity in multiple cancers. However, the role of JQ1 in ESCC remains unknown. In this study, we reported that JQ1 had potent anti-proliferative effects on ESCC cells in both time- and dose-dependent manners by inducing cell cycle arrest at G1 phase, cell apoptosis, and the mesenchymal-epithelial transition. Follow-up studies revealed that both c-Myc/cyclin/Rb and PI3K/AKT signaling pathways were inactivated by JQ1, as indicated by the downregulation of c-Myc, cyclin A/E, and phosphorylated Rb, AKT and S6. Tumor suppression induced by JQ1 in c-Myc amplified or highly expressed xenografts was higher than that in xenografts with low expression, suggesting its potential role in prediction. In conclusion, targeting c-Myc by JQ1 could cause significant tumor suppression in ESCC both in vitro and in vivo. Also, c-Myc amplification or high expression might serve as a potential biomarker and provide a promising therapeutic option for ESCC. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Gamabufotalin triggers c-Myc degradation via induction of WWP2 in multiple myeloma cells.

    Science.gov (United States)

    Yu, Zhenlong; Li, Tao; Wang, Chao; Deng, Sa; Zhang, Baojing; Huo, Xiaokui; Zhang, Bo; Wang, Xiaobo; Zhong, Yuping; Ma, Xiaochi

    2016-03-29

    Deciding appropriate therapy for multiple myeloma (MM) is challenging because of the occurrence of multiple chromosomal changes and the fatal nature of the disease. In the current study, gamabufotalin (GBT) was isolated from toad venom, and its tumor-specific cytotoxicity was investigated in human MM cells. We found GBT inhibited cell growth and induced apoptosis with the IC50 values <50 nM. Mechanistic studies using functional approaches identified GBT as an inhibitor of c-Myc. Further analysis showed that GBT especially evoked the ubiquitination and degradation of c-Myc protein, thereby globally repressing the expression of c-Myc target genes. GBT treatment inhibited ERK and AKT signals, while stimulating the activation of JNK cascade. An E3 ubiquitin-protein ligase, WWP2, was upregulated following JNK activation and played an important role in c-Myc ubiquitination and degradation through direct protein-protein interaction. The antitumor effect of GBT was validated in a xenograft mouse model and the suppression of MM-induced osteolysis was verified in a SCID-hu model in vivo. Taken together, our study identified the potential of GBT as a promising therapeutic agent in the treatment of MM.

  6. Vitamin K2 and cotylenin A synergistically induce monocytic differentiation and growth arrest along with the suppression of c-MYC expression and induction of cyclin G2 expression in human leukemia HL-60 cells.

    Science.gov (United States)

    Maniwa, Yasuhisa; Kasukabe, Takashi; Kumakura, Shunichi

    2015-08-01

    Although all-trans retinoic acid (ATRA) is a standard and effective drug used for differentiation therapy in acute promyelocytic leukemia, ATRA-resistant leukemia cells ultimately emerge during this treatment. Therefore, the development of new drugs or effective combination therapy is urgently needed. We demonstrate that the combined treatment of vitamin K2 and cotylenin A synergistically induced monocytic differentiation in HL-60 cells. This combined treatment also synergistically induced NBT-reducing activity and non-specific esterase-positive cells as well as morphological changes to monocyte/macrophage-like cells. Vitamin K2 and cotylenin A cooperatively inhibited the proliferation of HL-60 cells in short-term and long-term cultures. This treatment also induced growth arrest at the G1 phase. Although 5 µg/ml cotylenin A or 5 µM vitamin K2 alone reduced c-MYC gene expression in HL-60 cells to approximately 45% or 80% that of control cells, respectively, the combined treatment almost completely suppressed c-MYC gene expression. We also demonstrated that the combined treatment of vitamin K2 and cotylenin A synergistically induced the expression of cyclin G2, which had a positive effect on the promotion and maintenance of cell cycle arrest. These results suggest that the combination of vitamin K2 and cotylenin A has therapeutic value in the treatment of acute myeloid leukemia.

  7. Suppression of c-Myc induces apoptosis via an AMPK/mTOR-dependent pathway by 4-O-methyl-ascochlorin in leukemia cells.

    Science.gov (United States)

    Shin, Jae-Moon; Jeong, Yun-Jeong; Cho, Hyun-Ji; Magae, Junji; Bae, Young-Seuk; Chang, Young-Chae

    2016-05-01

    4-O-Methyl-ascochlorin (MAC) is a methylated derivative of the prenyl-phenol antibiotic ascochlorin, which was isolated from an incomplete fungus, Ascochyta viciae. Although the effects of MAC on apoptosis have been reported, the underlying mechanisms remain unknown. Here, we show that MAC promoted apoptotic cell death and downregulated c-Myc expression in K562 human leukemia cells. The effect of MAC on apoptosis was similar to that of 10058-F4 (a c-Myc inhibitor) or c-Myc siRNA, suggesting that the downregulation of c-Myc expression plays a role in the apoptotic effect of MAC. Further investigation showed that MAC downregulated c-Myc by inhibiting protein synthesis. MAC promoted the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and its target proteins, including p70S6 K and 4E-BP-1. Treatment of cells with AICAR (an AMPK activator), rapamycin (an mTOR inhibitor), or mTOR siRNA downregulated c-Myc expression and induced apoptosis to a similar extent to that of MAC. These results suggest that the effect of MAC on apoptosis induction in human leukemia cells is mediated by the suppression of c-Myc protein synthesis via an AMPK/mTOR-dependent mechanism.

  8. Astroglial c-Myc overexpression predisposes mice to primary malignant gliomas

    DEFF Research Database (Denmark)

    Jensen, Niels Aagaard; Pedersen, Karen-Marie; Lihme, Frederikke

    2003-01-01

    Malignant astrocytomas are common human primary brain tumors that result from neoplastic transformation of astroglia or their progenitors. Here we show that deregulation of the c-Myc pathway in developing astroglia predisposes mice to malignant astrocytomas within 2-3 weeks of age. The genetically...... engineered murine (GEM) gliomas harbor a molecular signature resembling that of human primary glioblastoma multiforme, including up-regulation of epidermal growth factor receptor and Mdm2. The GEM gliomas seem to originate in an abnormal population of glial fibrillary acidic protein-expressing cells...... the neoplastic process, presumably by inducing the sustained growth of early astroglial cells. This is in contrast to most other transgenic studies in which c-Myc overexpression requires co-operating transgenes for rapid tumor induction....

  9. Induction of apoptosis by 3-amino-6-(3-aminopropyl)-5,6-dihydro-5,11-dioxo-11H-indeno[1,2-c]isoquinoline via modulation of MAPKs (p38 and c-Jun N-terminal kinase) and c-Myc in HL-60 human leukemia cells.

    Science.gov (United States)

    Park, Eun-Jung; Kiselev, Evgeny; Conda-Sheridan, Martin; Cushman, Mark; Pezzuto, John M

    2012-03-23

    Recently, we reported that 3-amino-6-(3-aminopropyl)-5,6-dihydro-5,11-dioxo-11H-indeno[1,2-c]isoquinoline (AM6-36), sharing structural similarity with naturally occurring isoquinolines, induced activities mediated by retinoid X receptor (RXR) response element accompanied by antiproliferative effects on breast cancer cells. To further characterize the biologic potential of AM6-36, we currently report studies conducted with HL-60 human leukemia cells. AM6-36 significantly inhibited cellular proliferation in a dose- and time-dependent manner with an IC(50) value of 86 nM. When evaluated at low test concentrations (≤0.25 μM), AM6-36 induced arrest in the G2/M phase of the cell cycle. At higher concentrations (1 and 2 μM), the response shifted to apoptosis, which was consistent with the effect of AM6-36 on other apoptotic signatures including an increase of apoptotic annexin V(+) 7-AAD(-) cells, loss of mitochondrial membrane potential, induction of poly(ADP-ribose) polymerase cleavage, and activation of several caspases. These apoptotic effects are potentially due to up-regulation of p38 MAPK and JNK phosphorylation and down-regulation of c-Myc oncogene expression. Taken together, AM6-36 might serve as an effective anticancer agent by inducing G2/M cell cycle arrest and apoptosis through the activation of MAPKs and inhibition of c-Myc.

  10. c-Myc oncogene expression in selected odontogenic cysts and tumors: An immunohistochemical study

    Science.gov (United States)

    Moosvi, Zama; Rekha, K

    2013-01-01

    Aim: To investigate the role of c-Myc oncogene in selected odontogenic cysts and tumors. Materials and Methods: Ten cases each of ameloblastoma, adenomatoid odontogenic tumor (AOT), odontogenic keratocyst (OKC), dentigerous cyst, and radicular cyst were selected and primary monoclonal mouse anti-human c-Myc antibody was used in a dilution of 1: 50. Statistical Analysis was performed using Mann Whitney U test. Results: 80% positivity was observed in ameloblastoma, AOT and OKC; 50% positivity in radicular cyst and 20% positivity in dentigerous cyst. Comparison of c-Myc expression between ameloblastoma and AOT did not reveal significant results. Similarly, no statistical significance was observed when results of OKC were compared with ameloblastoma and AOT. In contrast, significant differences were seen on comparison of dentigerous cyst with ameloblastoma and AOT and radicular cyst with AOT. Conclusion: From the above data we conclude that (1) Ameloblastoma and AOT have similar proliferative potential and their biologic behavior cannot possibly be attributed to it. (2) OKC has an intrinsic growth potential which is absent in other cysts and reinforces its classification as keratocystic odontogenic tumor. PMID:23798830

  11. Postnatal liver growth and regeneration are independent of c-myc in a mouse model of conditional hepatic c-myc deletion

    Directory of Open Access Journals (Sweden)

    Sanders Jennifer A

    2012-03-01

    Full Text Available Abstract Background The transcription factor c-myc regulates genes involved in hepatocyte growth, proliferation, metabolism, and differentiation. It has also been assigned roles in liver development and regeneration. In previous studies, we made the unexpected observation that c-Myc protein levels were similar in proliferating fetal liver and quiescent adult liver with c-Myc displaying nucleolar localization in the latter. In order to investigate the functional role of c-Myc in adult liver, we have developed a hepatocyte-specific c-myc knockout mouse, c-mycfl/fl;Alb-Cre. Results Liver weight to body weight ratios were similar in control and c-myc deficient mice. Liver architecture was unaffected. Conditional c-myc deletion did not result in compensatory induction of other myc family members or in c-Myc's binding partner Max. Floxed c-myc did have a negative effect on Alb-Cre expression at 4 weeks of age. To explore this relationship further, we used the Rosa26 reporter line to assay Cre activity in the c-myc floxed mice. No significant difference in Alb-Cre activity was found between control and c-mycfl/fl mice. c-myc deficient mice were studied in a nonproliferative model of liver growth, fasting for 48 hr followed by a 24 hr refeeding period. Fasting resulted in a decrease in liver mass and liver protein, both of which recovered upon 24 h of refeeding in the c-mycfl/fl;Alb-Cre animals. There was also no effect of reducing c-myc on recovery of liver mass following 2/3 partial hepatectomy. Conclusions c-Myc appears to be dispensable for normal liver growth during the postnatal period, restoration of liver mass following partial hepatectomy and recovery from fasting.

  12. c-MYC amplification and c-myc protein expression in pancreatic acinar cell carcinomas. New insights into the molecular signature of these rare cancers.

    Science.gov (United States)

    La Rosa, Stefano; Bernasconi, Barbara; Vanoli, Alessandro; Sciarra, Amedeo; Notohara, Kenji; Albarello, Luca; Casnedi, Selenia; Billo, Paola; Zhang, Lizhi; Tibiletti, Maria Grazia; Sessa, Fausto

    2018-05-02

    The molecular alterations of pancreatic acinar cell carcinomas (ACCs) and mixed acinar-neuroendocrine carcinomas (MANECs) are not completely understood, and the possible role of c-MYC amplification in tumor development, progression, and prognosis is not known. We have investigated c-MYC gene amplification in a series of 35 ACCs and 4 MANECs to evaluate its frequency and a possible prognostic role. Gene amplification was investigated using interphasic fluorescence in situ hybridization analysis simultaneously hybridizing c-MYC and the centromere of chromosome 8 probes. Protein expression was immunohistochemically investigated using a specific monoclonal anti-c-myc antibody. Twenty cases had clones with different polysomies of chromosome 8 in absence of c-MYC amplification, and 5 cases had one amplified clone and other clones with chromosome 8 polysomy, while the remaining 14 cases were diploid for chromosome 8 and lacked c-MYC amplification. All MANECs showed c-MYC amplification and/or polysomy which were observed in 54% pure ACCs. Six cases (15.3%) showed nuclear immunoreactivity for c-myc, but only 4/39 cases showed simultaneous c-MYC amplification/polysomy and nuclear protein expression. c-myc immunoreactivity as well as c-MYC amplification and/or chromosome 8 polysomy was not statistically associated with prognosis. Our study demonstrates that a subset of ACCs shows c-MYC alterations including gene amplification and chromosome 8 polysomy. Although they are not associated with a different prognostic signature, the fact that these alterations are present in all MANECs suggests a role in the acinar-neuroendocrine differentiation possibly involved in the pathogenesis of MANECs.

  13. Transcriptional regulation of BRD7 expression by Sp1 and c-Myc

    Directory of Open Access Journals (Sweden)

    Li Shufang

    2008-12-01

    Full Text Available Abstract Background Bromodomain is an evolutionally conserved domain that is found in proteins strongly implicated in signal-dependent transcriptional regulation. Genetic alterations of bromodomain genes contributed to the development of many human cancers and other disorders. BRD7 is a recently identified bromodomain gene. It plays a critical role in cellular growth, cell cycle progression, and signal-dependent gene expression. Previous studies showed that BRD7 gene exhibited much higher-level of mRNA expression in normal nasopharyngeal epithelia than in nasopharyngeal carcinoma (NPC biopsies and cell lines. However, little is known about its transcriptional regulation. In this study, we explored the transcriptional regulation of BRD7 gene. Method Potential binding sites of transcription factors within the promoter region of BRD7 gene were predicted with MatInspector Professional http://genomatix.de/cgi-bin/matinspector_prof/mat_fam.pl. Mutation construct methods and luciferase assays were performed to define the minimal promoter of BRD7 gene. RT-PCR and western blot assays were used to detect the endogenous expression of transcription factor Sp1, c-Myc and E2F6 in all cell lines used in this study. Electrophoretic mobility shift assays (EMSA and Chromatin immunoprecipitation (ChIP were used to detect the direct transcription factors that are responsible for the promoter activity of BRD7 gene. DNA vector-based siRNA technology and cell transfection methods were employed to establish clone pools that stably expresses SiRNA against c-Myc expression in nasopharyngeal carcinoma 5-8F cells. Real-time PCR was used to detect mRNA expression of BRD7 gene in 5-8F/Si-c-Myc cells. Results We defined the minimal promoter of BRD7 gene in a 55-bp region (from -266 to -212bp, and identified that its promoter activity is inversely related to c-Myc expression. Sp1 binds to the Sp1/Myc-Max overlapping site of BRD7 minimal promoter, and slightly positively

  14. Cdx1 and c-Myc foster the initiation of transdifferentiation of the normal esophageal squamous epithelium toward Barrett's esophagus.

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    Douglas B Stairs

    Full Text Available Barrett's esophagus is a premalignant condition whereby the normal stratified squamous esophageal epithelium undergoes a transdifferentiation program resulting in a simple columnar epithelium reminiscent of the small intestine. These changes are typically associated with the stratified squamous epithelium chronically exposed to acid and bile salts as a result of gastroesophageal reflux disease (GERD. Despite this well-defined epidemiologic association between acid reflux and Barrett's esophagus, the genetic changes that induce this transdifferentiation process in esophageal keratinocytes have remained undefined.To begin to identify the genetic changes responsible for transdifferentiaiton in Barrett's esophagus, we performed a microarray analysis of normal esophageal, Barrett's esophagus and small intestinal biopsy specimens to identify candidate signaling pathways and transcription factors that may be involved. Through this screen we identified the Cdx1 homeodomain transcription factor and the c-myc pathway as possible candidates. Cdx1 and c-myc were then tested for their ability to induce transdifferentiation in immortalized human esophageal keratinocytes using organotypic culturing methods. Analyses of these cultures reveal that c-myc and cdx1 cooperate to induce mucin production and changes in keratin expression that are observed in the epithelium of Barrett's esophagus.These data demonstrate the ability of Cdx1 and c-myc to initiate the earliest stages of transdifferentiation of esophageal keratinocytes toward a cell fate characteristic of Barrett's esophagus.

  15. c-MYC G-quadruplex binding by the RNA polymerase I inhibitor BMH-21 and analogues revealed by a combined NMR and biochemical Approach.

    Science.gov (United States)

    Musso, Loana; Mazzini, Stefania; Rossini, Anna; Castagnoli, Lorenzo; Scaglioni, Leonardo; Artali, Roberto; Di Nicola, Massimo; Zunino, Franco; Dallavalle, Sabrina

    2018-03-01

    Pyridoquinazolinecarboxamides have been reported as RNA polymerase I inhibitors and represent a novel class of potential antitumor agents. BMH-21, was reported to intercalate with GC-rich rDNA, resulting in nucleolar stress as a primary mechanism of cytotoxicity. The interaction of BMH-21 and analogues with DNA G-quadruplex structures was studied by NMR and molecular modelling. The cellular response was investigated in a panel of human tumor cell lines and protein expression was examined by Western Blot analysis. We explored the ability of BMH-21 and its analogue 2 to bind to G-quadruplex present in the c-MYC promoter, by NMR and molecular modelling studies. We provide evidence that both compounds are not typical DNA intercalators but are effective binders of the tested G-quadruplex. The interaction with c-MYC G-quadruplex was reflected in down-regulation of c-Myc expression in human tumor cells. The inhibitory effect was almost complete in lymphoma cells SUDHL4 characterized by overexpression of c-Myc protein. This downregulation reflected an early and persistent modulation of cMyc mRNA. Given the relevance of c-MYC in regulation of ribosome biogenesis, it is conceivable that the inhibition of c-MYC contributes to the perturbation of nuclear functions and RNA polymerase I activity. Similar experiments with CX-5461, another RNA polymerase I transcription inhibitor, indicate the same behaviour in G-quadruplex stabilization. Our results support the hypothesis that BMH-21 and analogue compounds share the same mechanism, i.e. G-quadruplex binding as a primary event of a cascade leading to inhibition of RNA polymerase I and apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Endogenous c-Myc is essential for p53-induced apoptosis in response to DNA damage in vivo

    NARCIS (Netherlands)

    Phesse, T. J.; Myant, K. B.; Cole, A. M.; Ridgway, R. A.; Pearson, H.; Muncan, V.; van den Brink, G. R.; Vousden, K. H.; Sears, R.; Vassilev, L. T.; Clarke, A. R.; Sansom, O. J.

    2014-01-01

    Recent studies have suggested that C-MYC may be an excellent therapeutic cancer target and a number of new agents targeting C-MYC are in preclinical development. Given most therapeutic regimes would combine C-MYC inhibition with genotoxic damage, it is important to assess the importance of C-MYC

  17. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Zheng [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei, Guangzhou 510515 (China); Zhou, Yuning [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Evers, B. Mark [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Wang, Qingding, E-mail: qingding.wang@uky.edu [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Rictor associates with FBXW7 to form an E3 complex. Black-Right-Pointing-Pointer Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. Black-Right-Pointing-Pointer Knockdown of rictor increases protein levels of c-Myc and cylin E. Black-Right-Pointing-Pointer Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Black-Right-Pointing-Pointer Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor-FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  18. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    International Nuclear Information System (INIS)

    Guo, Zheng; Zhou, Yuning; Evers, B. Mark; Wang, Qingding

    2012-01-01

    Highlights: ► Rictor associates with FBXW7 to form an E3 complex. ► Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. ► Knockdown of rictor increases protein levels of c-Myc and cylin E. ► Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. ► Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor–FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  19. Celastrol inhibits chondrosarcoma proliferation, migration and invasion through suppression CIP2A/c-MYC signaling pathway

    Directory of Open Access Journals (Sweden)

    Jinhui Wu

    2017-05-01

    Full Text Available Chondrosarcomas (CS is the second most frequent tumors of cartilage origin. A small compound extracted from Thunder God Vine (Tripterygium wilfordii Hook. F. called celastrol can directly bound CIP2A protein and effectively inhibit cell proliferation and induce apoptosis in several cancer cells. However, little knowledge is concern about the important role of CIP2A in CS patients and the therapeutic value of celastrol on CS. Our results showed that CIP2A and c-MYC were verified to be oncoproteins by detecting their mRNA and protein expression in 10 human CS tissues by qRT-PCR and Western blots. After treatment of celastrol, the proliferation, migration and invasion were significantly inhibited; whereas the apoptosis was largely induced in human CS cell lines. In addition, celastrol inhibited the expression of CIP2A, c-MYC, and suppressed apoptotic proteins BAX and caspase-8 in human CS cells, on the other hand, it induced the expression of antiapoptotic protein Bcl-2. Finally, knockdown of CIP2A also inhibited the migration and invasion and induced apoptosis of human CS cells. To sum up, we found that celastrol had effects on inhibiting proliferation, migration, invasion and inducing apoptosis through suppression CIP2A/c-MYC signaling pathway in vitro, which may provide a new therapeutic regimen for CS.

  20. Nm23-M2/NDP kinase B induces endogenous c-myc and nm23-M1/NDP kinase A overexpression in BAF3 cells. Both NDP kinases protect the cells from oxidative stress-induced death

    International Nuclear Information System (INIS)

    Arnaud-Dabernat, Sandrine; Masse, Karine; Smani, Moneim; Peuchant, Evelyne; Landry, Marc; Bourbon, Pierre-Marie; Le Floch, Renaud; Daniel, Jean-Yves; Larou, Monique

    2004-01-01

    The nm23 gene family encodes nucleoside diphosphate kinases (NDPKs) which supply the cell with (d)NTPs. The human NDPKB, also known as the PuF protein, binds the c-myc promoter and transactivates the c-myc protooncogene. We have now studied the effects of mouse NDPKA and NDPKB overexpression on endogenous c-myc transactivation in the mouse BAF3 and the rat PC12 cell lines. c-myc transcripts were found to be up-regulated by NDPKB only in the BAF3 line. This suggests that c-myc transcriptional control via NDPKB depends on the presence of cell-specific co-factors. Unexpectedly, NDPKB also induced NDPKA expression. This new effect was found in both cell lines, suggesting that NDPKB-dependent nm23-M1 gene transactivation requires cis and/or trans elements different from those involved in c-myc transactivation. Moreover, the BAF3 cell proliferation capacities were found to be independent of NDPKA or B cell contents. Interestingly, cell death induced by c-myc overexpression or H 2 O 2 exposure was decreased in nm23-transfected compared to control BAF3 cells. These data collectively suggest that NDPKs might improve cell survival by a mechanism coupling DNA repair and transcriptional regulation of genes involved in DNA damage response

  1. Blocking c-myc and stat3 by E. coli expressed and enzyme digested siRNA in mouse melanoma

    International Nuclear Information System (INIS)

    Hong Jie; Zhao Yingchun; Huang Weida

    2006-01-01

    Tumour cells often show alteration in the signal-transduction pathways, leading to proliferation in response to external signals. Oncogene overexpression and constitutive expression is a common phenomenon in the development and progression of many human cancers. Therefore oncogenes provide potential targets for cancer therapy. RNA interference (RNAi), mediated by small interfering RNA (siRNA), silences genes with a high degree of specificity and potentially represents a general approach for molecularly targeted anti-cancer therapy. The data presented in this report evaluated the method of systemically administering combined esiRNAs to multiple targets as compared with the method of using a single kind of esiRNA to a single target. Our experimental data revealed that the mixed treatment of esiC-MYC and esiSTAT3 had a better inhibition effect than the single treatment of esiC-MYC or esiSTAT3 on mouse B16 melanoma

  2. Neuropharmacology of purinergic receptors in human submucous plexus: Involvement of P2X₁, P2X₂, P2X₃ channels, P2Y and A₃ metabotropic receptors in neurotransmission.

    Science.gov (United States)

    Liñán-Rico, A; Wunderlich, J E; Enneking, J T; Tso, D R; Grants, I; Williams, K C; Otey, A; Michel, K; Schemann, M; Needleman, B; Harzman, A; Christofi, F L

    2015-08-01

    The role of purinergic signaling in human ENS is not well understood. We sought to further characterize the neuropharmacology of purinergic receptors in human ENS and test the hypothesis that endogenous purines are critical regulators of neurotransmission. LSCM-Fluo-4/(Ca(2+))-imaging of postsynaptic Ca(2+) transients (PSCaTs) was used as a reporter of synaptic transmission evoked by fiber tract electrical stimulation in human SMP surgical preparations. Pharmacological analysis of purinergic signaling was done in 1,556 neurons (identified by HuC/D-immunoreactivity) in 235 ganglia from 107 patients; P2XR-immunoreactivity was evaluated in 19 patients. Real-time MSORT (Di-8-ANEPPS) imaging tested effects of adenosine on fast excitatory synaptic potentials (fEPSPs). Synaptic transmission is sensitive to pharmacological manipulations that alter accumulation of extracellular purines: Apyrase blocks PSCaTs in a majority of neurons. An ecto-NTPDase-inhibitor 6-N,N-diethyl-D-β,γ-dibromomethyleneATP or adenosine deaminase augments PSCaTs. Blockade of reuptake/deamination of eADO inhibits PSCaTs. Adenosine inhibits fEPSPs and PSCaTs (IC50 = 25 µM), sensitive to MRS1220-antagonism (A3AR). A P2Y agonist ADPβS inhibits PSCaTs (IC50 = 111 nM) in neurons without stimulatory ADPbS responses (EC50 = 960 nM). ATP or a P2X1,2,2/3 (α,β-MeATP) agonist evokes fast, slow, biphasic Ca(2+) transients or Ca(2+) oscillations (ATP,EC50 = 400 mM). PSCaTs are sensitive to P2X1 antagonist NF279. Low (20 nM) or high (5 µM) concentrations of P2X antagonist TNP-ATP block PSCaTs in different neurons; proportions of neurons with P2XR-immunoreactivity follow the order P2X2 > P2X1 > P2X3; P2X1 + P2X2 and P2X3 + P2X2 are co-localized. RT-PCR identified mRNA-transcripts for P2X1-7, P2Y1,2,12-14R. Purines are critical regulators of neurotransmission in human ENS. Purinergic signaling involves P2X1, P2X2, P2X3 channels, P2X1 + P2X2 co-localization and inhibitory P2Y or A3 receptors. These are

  3. USP10 Antagonizes c-Myc Transcriptional Activation through SIRT6 Stabilization to Suppress Tumor Formation

    Directory of Open Access Journals (Sweden)

    Zhenghong Lin

    2013-12-01

    Full Text Available The reduced protein expression of SIRT6 tumor suppressor is involved in tumorigenesis. The molecular mechanisms underlying SIRT6 protein downregulation in human cancers remain unknown. Using a proteomic approach, we have identified the ubiquitin-specific peptidase USP10, another tumor suppressor, as one of the SIRT6-interacting proteins. USP10 suppresses SIRT6 ubiquitination to protect SIRT6 from proteasomal degradation. USP10 antagonizes the transcriptional activity of the c-Myc oncogene through SIRT6, as well as p53, to inhibit cell-cycle progression, cancer cell growth, and tumor formation. To support this conclusion, we detected significant reductions in both USP10 and SIRT6 protein expression in human colon cancers. Our study discovered crosstalk between two tumor-suppressive genes in regulating cell-cycle progression and proliferation and showed that dysregulated USP10 function promotes tumorigenesis through SIRT6 degradation.

  4. Calmodulin-mediated activation of Akt regulates survival of c-Myc-overexpressing mouse mammary carcinoma cells.

    Science.gov (United States)

    Deb, Tushar B; Coticchia, Christine M; Dickson, Robert B

    2004-09-10

    c-Myc-overexpressing mammary epithelial cells are proapoptotic; their survival is strongly promoted by epidermal growth factor (EGF). We now demonstrate that EGF-induced Akt activation and survival in transgenic mouse mammary tumor virus-c-Myc mouse mammary carcinoma cells are both calcium/calmodulin-dependent. Akt activation is abolished by the phospholipase C-gamma inhibitor U-73122, by the intracellular calcium chelator BAPTA-AM, and by the specific calmodulin antagonist W-7. These results implicate calcium/calmodulin in the activation of Akt in these cells. In addition, Akt activation by serum and insulin is also inhibited by W-7. EGF-induced and calcium/calmodulin-mediated Akt activation occurs in both tumorigenic and non-tumorigenic mouse and human mammary epithelial cells, independent of their overexpression of c-Myc. These results imply that calcium/calmodulin may be a common regulator of Akt activation, irrespective of upstream receptor activator, mammalian species, and transformation status in mammary epithelial cells. However, only c-Myc-overexpressing mouse mammary carcinoma cells (but not normal mouse mammary epithelial cells) undergo apoptosis in the presence of the calmodulin antagonist W-7, indicating the vital selective role of calmodulin for survival of these cells. Calcium/calmodulin-regulated Akt activation is mediated directly by neither calmodulin kinases nor phosphatidylinositol 3-kinase (PI-3 kinase). Pharmacological inhibitors of calmodulin kinase kinase and calmodulin kinases II and III do not inhibit EGF-induced Akt activation, and calmodulin antagonist W-7 does not inhibit phosphotyrosine-associated PI-3 kinase activation. Akt is, however, co-immunoprecipitated with calmodulin in an EGF-dependent manner, which is inhibited by calmodulin antagonist W-7. We conclude that calmodulin may serve a vital regulatory function to direct the localization of Akt to the plasma membrane for its activation by PI-3 kinase.

  5. Effects on micronuclei formation of 60-Hz electromagnetic field exposure with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    Science.gov (United States)

    Jin, Yeung Bae; Kang, Ga-Young; Lee, Jae Seon; Choi, Jong-Il; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2012-04-01

    Epidemiological studies have demonstrated a possible correlation between exposure to extremely low-frequency magnetic fields (ELF-MF) and cancer. However, this correlation has yet to be definitively confirmed by epidemiological studies. The principal objective of this study was to assess the effects of 60 Hz magnetic fields in a normal cell line system, and particularly in combination with various external factors, via micronucleus (MN) assays. Mouse embryonic fibroblast NIH3T3 cells and human lung fibroblast WI-38 cells were exposed for 4 h to a 60 Hz, 1 mT uniform magnetic field with or without ionizing radiation (IR, 2 Gy), H(2)O(2) (100 μM) and cellular myelocytomatosis oncogene (c-Myc) activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic effects were observed when ELF-MF was combined with IR, H(2)O(2), and c-Myc activation. Our results demonstrate that ELF-MF did not enhance MN frequency by IR, H(2)O(2) and c-Myc activation.

  6. Glutathione Depletion Induced by c-Myc Downregulation Triggers Apoptosis on Treatment with Alkylating Agents1

    Science.gov (United States)

    Biroccio, Annamaria; Benassi, Barbara; Fiorentino, Francesco; Zupi, Gabriella

    2004-01-01

    Abstract Here we investigate the mechanism(s) involved in the c-Myc-dependent drug response of melanoma cells. By using three M14-derived c-Myc low-expressing clones, we demonstrate that alkylating agents, cisplatin and melphalan, trigger apoptosis in the c-Myc antisense transfectants, but not in the parental line. On the contrary, topoisomerase inhibitors, adriamycin and camptothecin, induce apoptosis to the same extent regardless of c-Myc expression. Because we previously demonstrated that c-Myc downregulation decreases glutathione (GSH) content, we evaluated the role of GSH in the apoptosis induced by the different drugs. In control cells treated with one of the alkylating agents or the others, GSH depletion achieved by l-buthionine-sulfoximine preincubation opens the apoptotic pathway. The apoptosis proceeded through early Bax relocalization, cytochrome c release, and concomitant caspase-9 activation, whereas reactive oxygen species production and alteration of mitochondria membrane potential were late events. That GSH was determining in the c-Myc-dependent drug-induced apoptosis was demonstrated by altering the intracellular GSH content of the c-Myc low-expressing cells up to the level of controls. Indeed, GSH ethyl ester-mediated increase of GSH abrogated apoptosis induced by cisplatin and melphalan by inhibition of Bax/cytochrome c redistribution. The relationship among c-Myc, GSH content, and the response to alkylating agent has been also evaluated in the M14 Myc overexpressing clones as well as in the melanoma JR8 c-Myc antisense transfectants. All together, these results demonstrate that GSH plays a key role in governing c-Myc-dependent drug-induced apoptosis. PMID:15153331

  7. Driver or passenger effects of augmented c-Myc and Cdc20 in gliomagenesis.

    Science.gov (United States)

    Ji, Ping; Zhou, Xinhui; Liu, Qun; Fuller, Gregory N; Phillips, Lynette M; Zhang, Wei

    2016-04-26

    Cdc20 and c-Myc are commonly overexpressed in a broad spectrum of cancers, including glioblastoma (GBM). Despite this clear association, whether c-Myc and Cdc20 overexpression is a driver or passenger event in gliomagenesis remains unclear. Both c-Myc and Cdc20 induced the proliferation of primary glial progenitor cells. c-Myc also promoted the formation of soft agar anchorage-independent colonies. In the RCAS/Ntv-a glia-specific transgenic mouse model, c-Myc increased the GBM incidence from 19.1% to 47.4% by 12 weeks of age when combined with kRas and Akt3 in Ntv-a INK4a-ARF (also known as CDKN2A)-null mice. In contrast, Cdc20 decreased the GBM incidence from 19.1% to 9.1%. Moreover, cell differentiation was modulated by c-Myc in kRas/Akt3-induced GBM on the basis of Nestin/GFAP expression (glial progenitor cell differentiation), while Cdc20 had no effect on primary glial progenitor cell differentiation. We used glial progenitor cells from Ntv-a newborn mice to evaluate the role of c-Myc and Cdc20 in the proliferation and transformation of GBM in vitro and in vivo. We further determined whether c-Myc and Cdc20 have a driver or passenger role in GBM development using kRas/Akt3 signals in a RCAS/Ntv-a mouse model. These results suggest that the driver or passenger of oncogene signaling is dependent on cellular status. c-Myc is a driver when combined with kRas/Akt3 oncogenic signals in gliomagenesis, whereas Cdc20 overexpression is a passenger. Inhibition of cell differentiation of c-Myc may be a target for anti-glioma therapy.

  8. Neuropharmacology of Purinergic Receptors in Human Submucous Plexus: Involvement of P2X1, P2X2, P2X3 Channels, P2Y and A3 Metabotropic Receptors in Neurotransmission

    Science.gov (United States)

    Liñán-Rico, A.; Wunderlich, JE.; Enneking, JT.; Tso, DR.; Grants, I.; Williams, KC.; Otey, A.; Michel, K.; Schemann, M.; Needleman, B.; Harzman, A.; Christofi, FL.

    2015-01-01

    Rationale The role of purinergic signaling in the human ENS is not well understood. We sought to further characterize the neuropharmacology of purinergic receptors in human ENS and test the hypothesis that endogenous purines are critical regulators of neurotransmission. Experimental Approach LSCM-Fluo-4-(Ca2+)-imaging of postsynaptic Ca2+ transients (PSCaTs) was used as a reporter of neural activity. Synaptic transmission was evoked by fiber tract electrical stimulation in human SMP surgical preparations. Pharmacological analysis of purinergic signaling was done in 1,556 neurons from 234 separate ganglia 107 patients; immunochemical labeling for P2XRs of neurons in ganglia from 19 patients. Real-time MSORT (Di-8-ANEPPS) imaging was used to test effects of adenosine on fast excitatory synaptic potentials (fEPSPs). Results Synaptic transmission is sensitive to pharmacological manipulations that alter accumulation of extracellular purines. Apyrase blocks PSCaTs in a majority of neurons. An ecto-NTPDase-inhibitor 6-N,N-diethyl-D-β,γ-dibromomethyleneATP or adenosine deaminase augments PSCaTs. Blockade of reuptake/deamination of eADO inhibits PSCaTs. Adenosine inhibits fEPSPs and PSCaTs (IC50=25μM), sensitive to MRS1220-antagonism (A3AR). A P2Y agonist ADPβS inhibits PSCaTs (IC50=111nM) in neurons without stimulatory ADPβS responses (EC50=960nM). ATP or a P2X1,2,2/3 (α,β-MeATP) agonist evokes fast, slow, biphasic Ca2+ transients or Ca2+ oscillations (EC50=400μM). PSCaTs are sensitive to P2X1 antagonist NF279. Low (20nM) or high (5μM) concentrations of P2X antagonist TNP-ATP block PSCaTs in different neurons; proportions of neurons with P2XR-ir follow the order P2X2>P2X1≫P2X3; P2X1+ P2X2 and P2X3+P2X2 are co-localized. RT-PCR identified mRNA-transcripts for P2X1-7,P2Y1,2,12-14R. Responsive neurons were also identified by HuC/D-ir. Conclusions Purines are critical regulators of neurotransmission in the human enteric nervous system. Purinergic signaling involves

  9. Cooverexpression of EpCAM and c-myc genes in malignant breast

    Indian Academy of Sciences (India)

    oncogene, affects progression, treatment, and diagnosis of many adenocarcinomas. C-myc has been shown to be a downstream target of EpCAM and is also one of the most important proto-oncogenes routinely overexpressed in breast cancer.

  10. Differential cellular responses by oncogenic levels of c-Myc expression in long-term confluent retinal pigment epithelial cells.

    Science.gov (United States)

    Wang, Yiping; Cheng, Xiangdong; Samma, Muhammad Kaleem; Kung, Sam K P; Lee, Clement M; Chiu, Sung Kay

    2018-06-01

    c-Myc is a highly pleiotropic transcription factor known to control cell cycle progression, apoptosis, and cellular transformation. Normally, ectopic expression of c-Myc is associated with promoting cell proliferation or triggering cell death via activating p53. However, it is not clear how the levels of c-Myc lead to different cellular responses. Here, we generated a series of stable RPE cell clones expressing c-Myc at different levels, and found that consistent low level of c-Myc induced cellular senescence by activating AP4 in post-confluent RPE cells, while the cells underwent cell death at high level of c-Myc. In addition, high level of c-Myc could override the effect of AP4 on cellular senescence. Further knockdown of AP4 abrogated senescence-like phenotype in cells expressing low level of c-Myc, and accelerated cell death in cells with medium level of c-Myc, indicating that AP4 was required for cellular senescence induced by low level of c-Myc.

  11. Driving gradual endogenous c-myc overexpression by flow-sorting: intracellular signaling and tumor cell phenotype correlate with oncogene expression

    DEFF Research Database (Denmark)

    Knudsen, Kasper Jermiin; Holm, G.M.N.; Krabbe, J.S.

    2009-01-01

    Insulin-exposed rat mammary cancer cells were flow sorted based on a c-myc reporter plasmid encoding a destabilized green fluorescent protein. Sorted cells exhibited gradual increases in c-myc levels. Cells overexpressing c-myc by only 10% exhibited phenotypic changes attributable to c-myc overex...

  12. Integrin α6Bβ4 inhibits colon cancer cell proliferation and c-Myc activity

    International Nuclear Information System (INIS)

    Dydensborg, Anders Bondo; Teller, Inga C; Groulx, Jean-François; Basora, Nuria; Paré, Fréderic; Herring, Elizabeth; Gauthier, Rémy; Jean, Dominique; Beaulieu, Jean-François

    2009-01-01

    Integrins are known to be important contributors to cancer progression. We have previously shown that the integrin β4 subunit is up-regulated in primary colon cancer. Its partner, the integrin α6 subunit, exists as two different mRNA splice variants, α6A and α6B, that differ in their cytoplasmic domains but evidence for distinct biological functions of these α6 splice variants is still lacking. In this work, we first analyzed the expression of integrin α6A and α6B at the protein and transcript levels in normal human colonic cells as well as colorectal adenocarcinoma cells from both primary tumors and established cell lines. Then, using forced expression experiments, we investigated the effect of α6A and α6B on the regulation of cell proliferation in a colon cancer cell line. Using variant-specific antibodies, we observed that α6A and α6B are differentially expressed both within the normal adult colonic epithelium and between normal and diseased colonic tissues. Proliferative cells located in the lower half of the glands were found to predominantly express α6A, while the differentiated and quiescent colonocytes in the upper half of the glands and surface epithelium expressed α6B. A relative decrease of α6B expression was also identified in primary colon tumors and adenocarcinoma cell lines suggesting that the α6A/α6B ratios may be linked to the proliferative status of colonic cells. Additional studies in colon cancer cells showed that experimentally restoring the α6A/α6B balance in favor of α6B caused a decrease in cellular S-phase entry and repressed the activity of c-Myc. The findings that the α6Bβ4 integrin is expressed in quiescent normal colonic cells and is significantly down-regulated in colon cancer cells relative to its α6Aβ4 counterpart are consistent with the anti-proliferative influence and inhibitory effect on c-Myc activity identified for this α6Bβ4 integrin. Taken together, these findings point out the importance of integrin

  13. Endogenous c-Myc is essential for p53-induced apoptosis in response to DNA damage in vivo.

    Science.gov (United States)

    Phesse, T J; Myant, K B; Cole, A M; Ridgway, R A; Pearson, H; Muncan, V; van den Brink, G R; Vousden, K H; Sears, R; Vassilev, L T; Clarke, A R; Sansom, O J

    2014-06-01

    Recent studies have suggested that C-MYC may be an excellent therapeutic cancer target and a number of new agents targeting C-MYC are in preclinical development. Given most therapeutic regimes would combine C-MYC inhibition with genotoxic damage, it is important to assess the importance of C-MYC function for DNA damage signalling in vivo. In this study, we have conditionally deleted the c-Myc gene in the adult murine intestine and investigated the apoptotic response of intestinal enterocytes to DNA damage. Remarkably, c-Myc deletion completely abrogated the immediate wave of apoptosis following both ionizing irradiation and cisplatin treatment, recapitulating the phenotype of p53 deficiency in the intestine. Consistent with this, c-Myc-deficient intestinal enterocytes did not upregulate p53. Mechanistically, this was linked to an upregulation of the E3 Ubiquitin ligase Mdm2, which targets p53 for degradation in c-Myc-deficient intestinal enterocytes. Further, low level overexpression of c-Myc, which does not impact on basal levels of apoptosis, elicited sustained apoptosis in response to DNA damage, suggesting c-Myc activity acts as a crucial cell survival rheostat following DNA damage. We also identify the importance of MYC during DNA damage-induced apoptosis in several other tissues, including the thymus and spleen, using systemic deletion of c-Myc throughout the adult mouse. Together, we have elucidated for the first time in vivo an essential role for endogenous c-Myc in signalling DNA damage-induced apoptosis through the control of the p53 tumour suppressor protein.

  14. Inhibition of c-Myc by 10058-F4 induces growth arrest and chemosensitivity in pancreatic ductal adenocarcinoma.

    Science.gov (United States)

    Zhang, Meng; Fan, Hai-Yan; Li, Sheng-Chao

    2015-07-01

    Pancreatic ductal adenocarcinoma (PDAC) is a formidable medical challenge due to its malignancies and the absence of effective treatment. c-Myc, as an important transcription factor, plays crucial roles in cell cycle progression, apoptosis and cellular transformation. The c-Myc inhibitor, 10058-F4, has been reported act as a tumor suppressor in several different tumors. In current study, the tumor-suppressive roles of 10058-F4 was observed in human pancreatic cancer cells in vitro as demonstrated by decreased cell viability, cell cycle arrest at the G1/S transition and increased caspase3/7 activity. And tumor responses to gemcitabine were also significantly enhanced by 10058-F4 in PANC-1 and SW1990 cells. In a subcutaneous xenograft model, however, 10058-F4 showed no significant influence on pancreatic tumorigenesis. When combined with gemcitabine, tumorigenesis was drastically attenuated compared with gemcitabine group or 10058-F4 group; this synergistic effect was accompanied with decreased PCNA-positive cells and reduced TUNEL-positive cells in the combined treated group. Subsequent studies revealed that decreased glycolysis may be involved in the inhibitory effect of 10058-F4 on PDAC. Taken together, this study demonstrates the roles of 10058-F4 in PDAC and provides evidence that 10058-F4 in combination with gemcitabine showed significant clinical benefit over the usage of gemcitabine alone. Copyright © 2015. Published by Elsevier Masson SAS.

  15. Gene expression profiles in primary pancreatic tumors and metastatic lesions of Ela-c-myc transgenic mice

    Directory of Open Access Journals (Sweden)

    Liao Dezhong J

    2008-01-01

    Full Text Available Abstract Background Pancreatic carcinoma usually is a fatal disease with no cure, mainly due to its invasion and metastasis prior to diagnosis. We analyzed the gene expression profiles of paired primary pancreatic tumors and metastatic lesions from Ela-c-myc transgenic mice in order to identify genes that may be involved in the pancreatic cancer progression. Differentially expressed selected genes were verified by semi-quantitative and quantitative RT-PCR. To further evaluate the relevance of some of the selected differentially expressed genes, we investigated their expression pattern in human pancreatic cancer cell lines with high and low metastatic potentials. Results Data indicate that genes involved in posttranscriptional regulation were a major functional category of upregulated genes in both primary pancreatic tumors (PT and liver metastatic lesions (LM compared to normal pancreas (NP. In particular, differential expression for splicing factors, RNA binding/pre-mRNA processing factors and spliceosome related genes were observed, indicating that RNA processing and editing related events may play critical roles in pancreatic tumor development and progression. High expression of insulin growth factor binding protein-1 (Igfbp1 and Serine proteinase inhibitor A1 (Serpina1, and low levels or absence of Wt1 gene expression were exclusive to liver metastatic lesion samples. Conclusion We identified Igfbp1, Serpina1 and Wt1 genes that are likely to be clinically useful biomarkers for prognostic or therapeutic purposes in metastatic pancreatic cancer, particularly in pancreatic cancer where c-Myc is overexpressed.

  16. Gene expression profiles in primary pancreatic tumors and metastatic lesions of Ela-c-myc transgenic mice.

    Science.gov (United States)

    Thakur, Archana; Bollig, Aliccia; Wu, Jiusheng; Liao, Dezhong J

    2008-01-24

    Pancreatic carcinoma usually is a fatal disease with no cure, mainly due to its invasion and metastasis prior to diagnosis. We analyzed the gene expression profiles of paired primary pancreatic tumors and metastatic lesions from Ela-c-myc transgenic mice in order to identify genes that may be involved in the pancreatic cancer progression. Differentially expressed selected genes were verified by semi-quantitative and quantitative RT-PCR. To further evaluate the relevance of some of the selected differentially expressed genes, we investigated their expression pattern in human pancreatic cancer cell lines with high and low metastatic potentials. Data indicate that genes involved in posttranscriptional regulation were a major functional category of upregulated genes in both primary pancreatic tumors (PT) and liver metastatic lesions (LM) compared to normal pancreas (NP). In particular, differential expression for splicing factors, RNA binding/pre-mRNA processing factors and spliceosome related genes were observed, indicating that RNA processing and editing related events may play critical roles in pancreatic tumor development and progression. High expression of insulin growth factor binding protein-1 (Igfbp1) and Serine proteinase inhibitor A1 (Serpina1), and low levels or absence of Wt1 gene expression were exclusive to liver metastatic lesion samples. We identified Igfbp1, Serpina1 and Wt1 genes that are likely to be clinically useful biomarkers for prognostic or therapeutic purposes in metastatic pancreatic cancer, particularly in pancreatic cancer where c-Myc is overexpressed.

  17. c-Myc Represses Tumor-Suppressive microRNAs, let-7a, miR-16 and miR-29b, and Induces Cyclin D2-Mediated Cell Proliferation in Ewing's Sarcoma Cell Line.

    Directory of Open Access Journals (Sweden)

    Masanori Kawano

    Full Text Available Myc oncogenic transcription factor is known to inhibit tumor suppressive microRNAs (miRNAs, resulting in greater expression of their target protein related to cell cycle, invasion or anti-apoptotic factors in human cancer cells. To explore possible oncogenic factors in Ewing's sarcoma (ES, we conducted microarray-based approach to profile the changes in the expression of miRNAs and its downstream mRNAs in five ES cell lines and human mesenchymal stem cells (hMSCs. Three miRNAs, let-7a, miR-16 and miR-29b were significantly down-regulated, whereas c-Myc and cyclin D2 (CCND2 were significantly up-regulated in all tested ES cells compared with hMSCs. To verify that let-7a, miR-16 and miR-29b were the targets of c-Myc in ES cell lines, we transfected siRNA against c-Myc and confirmed the coordinate up-regulation of let-7a, miR-16 and miR-29b through the repression of c-Myc. The ES cells transfected with c-Myc-siRNA and let-7a, miR-16 and miR-29b exhibited the inhibition of the cell cycle progression. The increased expression of let-7a, miR-16 and miR-29b resulted in the reduction of CCND2 protein expression. We also demonstrated that c-Myc-siRNA treatment of ES cells was associated with the decreased expression of CCND2 as a down-stream of three miRNAs. Furthermore, the introduction of let-7a, miR-16 and miR-29b in ES cells could inhibit the c-Myc-mediated up-regulation of CCND2 resulted in the prevention of cell cycle progression. In addition, the transfection of let-7a, miR-16 and miR-29b in ES cells suppressed tumor growth ex vivo treatment. These findings suggests that the up-regulation of c-Myc inhibited the expression of let-7a, miR-16 and miR-29b subsequently induced CCND2 expression in ES cells. The present study might identify a novel oncogenic axis that c-Myc regulates the expression of CCND2 via let-7a, miR-16 and miR-29b, leading to the development new therapeutic targets for ES.

  18. Interrelationship between chromosome 8 aneuploidy, C-MYC amplification and increased expression in individuals from northern Brazil with gastric adenocarcinoma

    Science.gov (United States)

    Calcagno, Danielle Queiroz; Leal, Mariana Ferreira; Seabra, Aline Damaceno; Khayat, André Salim; Chen, Elizabeth Suchi; Demachki, Samia; Assumpção, Paulo Pimentel; Faria, Mario Henrique Girão; Rabenhorst, Silvia Helena Barem; Ferreira, Márcia Valéria Pitombeira; Smith, Marília de Arruda Cardoso; Burbano, Rommel Rodríguez

    2006-01-01

    AIM: To investigate chromosome 8 numerical aberrations, C-MYC oncogene alterations and its expression in gastric cancer and to correlate these findings with histopathological characteristics of gastric tumors. METHODS: Specimens were collected surgically from seven patients with gastric adenocarcinomas. Immunostaining for C-MYC and dual-color fluorescence in situ hybridization (FISH) for C-MYC gene and chromosome 8 centromere were performed. RESULTS: All the cases showed chromosome 8 aneuploidy and C-MYC amplification, in both the diffuse and intestinal histopathological types of Lauren. No significant difference (P < 0.05) was observed between the level of chromosome 8 ploidy and the site, stage or histological type of the adenocarcinomas. C-MYC high amplification, like homogeneously stained regions (HSRs) and double minutes (DMs), was observed only in the intestinal-type. Structural rearrangement of C-MYC, like translocation, was observed only in the diffuse type. Regarding C-MYC gene, a significant difference (P < 0.05) was observed between the two histological types. The C-MYC protein was expressed in all the studied cases. In the intestinal-type the C-MYC immunoreactivity was localized only in the nucleus and in the diffuse type in the nucleus and cytoplasm. CONCLUSION: Distinct patterns of alterations between intestinal and diffuse types of gastric tumors support the hypothesis that these types follow different genetic pathways. PMID:17036397

  19. Detecção imunoistoquímica das oncoproteínas p21ras, c-myc E p53 no carcinoma hepatocelular e no tecido hepático não-neoplásico Immunohistochemical detection of p21ras, c-myc and p53 oncoproteins in hepatocellular carcinoma and in non-neoplastic liver tissue

    Directory of Open Access Journals (Sweden)

    Vera Lucia Nunes Pannain

    2004-12-01

    Full Text Available RACIONAL: A hepatocarcinogênese é um processo no qual as alterações genéticas e epigenéticas são bem conhecidas em modelos animais, mas carece de estudos no homem. OBJETIVOS: Analisar a freqüência das oncoproteínas p21ras, c-myc e p53 no carcinoma hepatocelular e no fígado não-neoplásico. Verificar ainda a associação destas oncoproteínas com os padrões e graus histológicos, assim como com as infecções pelos vírus das hepatites B e C. MÉTODOS: Foi analisada por método imunoistoquímico a detecção das oncoproteínas p21ras, c-myc e p53 em 47 casos de carcinoma hepatocelular e no tecido não-neoplásico circunjacente ao tumor (40 casos. RESULTADOS: As oncoproteínas p21ras, c-myc e p53 foram detectadas, respectivamente, em 44,7%, 53,2% e 36,2% dos casos de carcinoma hepatocelular. A imunorreatividade do p21ras e c-myc mostrou uma associação significativa. Contudo, não houve associação significativa entre a detecção do p21ras, c-myc e p53 com os diferentes graus e padrões histológicos, nem tampouco com as infecções pelos vírus das hepatites B e C. A mesma associação significativa entre o p21ras e c-myc foi encontrada no tecido não-neoplásico dos casos de cirrose em relação aos que não apresentaram cirrose, enquanto que o p53 foi negativo em todos os casos. CONCLUSÕES: A imunorreatividade das oncoproteínas p21ras, c-myc e p53 corrobora evidências prévias de sua detecção no carcinoma hepatocelular, o que sugere poder haver participação destas proteínas na hepatocarcinogênese humana. A significativa associação entre as proteínas p21ras, c-myc e p53 no carcinoma hepatocelular e na cirrose pode apontar uma interação entre as mesmas, sobretudo na hepatocarcinogênese pela via da cirrose.BACKGROUND: Genetic and epigenetic alterations have been described in animal hepatocarcinogenesis models but need to be studied in human being. AIMS: To assess the immunoreactivity of p21ras, c-myc and p53

  20. A proteomic study of cMyc improvement of CHO culture

    Directory of Open Access Journals (Sweden)

    Dunn Michael J

    2010-03-01

    Full Text Available Abstract Background The biopharmaceutical industry requires cell lines to have an optimal proliferation rate and a high integral viable cell number resulting in a maximum volumetric recombinant protein product titre. Nutrient feeding has been shown to boost cell number and productivity in fed-batch culture, but cell line engineering is another route one may take to increase these parameters in the bioreactor. The use of CHO-K1 cells with a c-myc plasmid allowing for over-expressing c-Myc (designated cMycCHO gives a higher integral viable cell number. In this study the differential protein expression in cMycCHO is investigated using two-dimensional gel electrophoresis (2-DE followed by image analysis to determine the extent of the effect c-Myc has on the cell and the proteins involved to give the new phenotype. Results Over 100 proteins that were differentially expressed in cMycCHO cells were detected with high statistical confidence, of which 41 were subsequently identified by tandem mass spectrometry (LC-MS/MS. Further analysis revealed proteins involved in a variety of pathways. Some examples of changes in protein expression include: an increase in nucleolin, involved in proliferation and known to aid in stabilising anti-apoptotic protein mRNA levels, the cytoskeleton and mitochondrial morphology (vimentin, protein biosysnthesis (eIF6 and energy metabolism (ATP synthetase, and a decreased regulation of all proteins, indentified, involved in matrix and cell to cell adhesion. Conclusion These results indicate several proteins involved in proliferation and adhesion that could be useful for future approaches to improve proliferation and decrease adhesion of CHO cell lines which are difficult to adapt to suspension culture.

  1. Macrocyclic peptides decrease c-Myc protein levels and reduce prostate cancer cell growth.

    Science.gov (United States)

    Mukhopadhyay, Archana; Hanold, Laura E; Thayele Purayil, Hamsa; Gisemba, Solomon A; Senadheera, Sanjeewa N; Aldrich, Jane V

    2017-08-03

    The oncoprotein c-Myc is often overexpressed in cancer cells, and the stability of this protein has major significance in deciding the fate of a cell. Thus, targeting c-Myc levels is an attractive approach for developing therapeutic agents for cancer treatment. In this study, we report the anti-cancer activity of the macrocyclic peptides [D-Trp]CJ-15,208 (cyclo[Phe-D-Pro-Phe-D-Trp]) and the natural product CJ-15,208 (cyclo[Phe-D-Pro-Phe-Trp]). [D-Trp]CJ-15,208 reduced c-Myc protein levels in prostate cancer cells and decreased cell proliferation with IC 50 values ranging from 2.0 to 16 µM in multiple PC cell lines. [D-Trp]CJ-15,208 induced early and late apoptosis in PC-3 cells following 48 hours treatment, and growth arrest in the G2 cell cycle phase following both 24 and 48 hours treatment. Down regulation of c-Myc in PC-3 cells resulted in loss of sensitivity to [D-Trp]CJ-15,208 treatment, while overexpression of c-Myc in HEK-293 cells imparted sensitivity of these cells to [D-Trp]CJ-15,208 treatment. This macrocyclic tetrapeptide also regulated PP2A by reducing the levels of its phosphorylated form which regulates the stability of cellular c-Myc protein. Thus [D-Trp]CJ-15,208 represents a new lead compound for the potential development of an effective treatment of prostate cancer.

  2. Blockade of human P2X7 receptor function with a monoclonal antibody.

    Science.gov (United States)

    Buell, G; Chessell, I P; Michel, A D; Collo, G; Salazzo, M; Herren, S; Gretener, D; Grahames, C; Kaur, R; Kosco-Vilbois, M H; Humphrey, P P

    1998-11-15

    A monoclonal antibody (MoAb) specific for the human P2X7 receptor was generated in mice. As assessed by flow cytometry, the MoAb labeled human blood-derived macrophage cells natively expressing P2X7 receptors and cells transfected with human P2X7 but not other P2X receptor types. The MoAb was used to immunoprecipitate the human P2X7 receptor protein, and in immunohistochemical studies on human lymphoid tissue, P2X7 receptor labeling was observed within discrete areas of the marginal zone of human tonsil sections. The antibody also acted as a selective antagonist of human P2X7 receptors in several functional studies. Thus, whole cell currents, elicited by the brief application of 2',3'-(4-benzoyl)-benzoyl-ATP in cells expressing human P2X7, were reduced in amplitude by the presence of the MoAb. Furthermore, preincubation of human monocytic THP-1 cells with the MoAb antagonized the ability of P2X7 agonists to induce the release of interleukin-1beta.

  3. Low expression of c-Myc protein predicts poor outcomes in patients with hepatocellular carcinoma after resection.

    Science.gov (United States)

    Ji, Fei; Zhang, Zhi-Heng; Zhang, Yi; Shen, Shun-Li; Cao, Qing-Hua; Zhang, Long-Juan; Li, Shao-Qiang; Peng, Bao-Gang; Liang, Li-Jian; Hua, Yun-Peng

    2018-04-24

    Embryonic Liver Fodrin (ELF) is an adaptor protein of transforming growth factor (TGF-β) signaling cascade. Disruption of ELF results in mislocalization of Smad3 and Smad4, leading to compromised TGF-β signaling. c-Myc is an important oncogenic transcription factor, and the disruption of TGF-β signaling promotes c-Myc-induced hepatocellular carcinoma (HCC) carcinogenesis. However, the prognostic significance of c-Myc in HCC is less understood METHODS: The expression of c-Myc protein and mRNA were measured by immunohistochemistry (IHC) and qRT- PCR, respectively. IHC was performed to detect TGF-β1 and ELF expression in HCC tissues. Their relationship with clinicopathological factors and overall survival (OS) and disease free survival (DFS) were examined. The expression of c-Myc protein and mRNA in HCC tissues were significantly higher in HCC area than those in normal liver tissues. However, the expression were low compared with those adjacent to HCC area. c-Myc protein was independently predictive of DFS and OS, and it was negatively correlated with tumor size (P = 0.031), tumor number (P = 0.038), and recurrence (P = 0.001). Low c-Myc expression was associated with short-term recurrence and poor prognosis. The predictive value of c-Myc combined with TGF-β1 or/and ELF was higher than that of any other single marker. Low c-Myc, high TGF-β1 or/and low ELF expression was associated with the worst DFS and OS. Low expression of c-Myc protein predicts poor outcomes in patients with HCC with hepatectomy. The combination of the expression of c-Myc, TGF-β1, and ELF can be used to accurately predict outcomes of patients with HCC.

  4. Synergistic action between inhibition of P2Y12/P2Y1 and P2Y12/thrombin in ADP- and thrombin-induced human platelet activation

    Science.gov (United States)

    Nylander, Sven; Mattsson, Christer; Ramström, Sofia; Lindahl, Tomas L

    2004-01-01

    The objective of this study was to investigate if there is a synergistic effect of a combination of P2Y12 and P2Y1 inhibition and P2Y12 and thrombin inhibition, on ADP- and thrombin-induced platelet activation, respectively. The rationale being that these combinations will cause a concurrent inhibition of both Gαq and Gαi signalling.Blood from healthy volunteers was preincubated with AR-C69931MX, a reversible P2Y12 antagonist; MRS2179, a reversible P2Y1 antagonist; or melagatran, a direct reversible thrombin inhibitor; alone or in various combinations prior to activation with ADP or thrombin. Platelet function in whole blood was assessed by flow cytometry using the antibody PAC-1 to estimate the expression of active αIIbβ3 (the fibrinogen receptor GPIIb/IIIa). A synergistic effect was evaluated by comparing the concentrations in the different combinations with those of corresponding equipotent concentrations of each single inhibitor alone. The equipotent single concentrations were experimentally obtained from concentration response curves performed in parallel.A synergistic effect regarding inhibition of ADP-induced platelet activation (10 μM) was obtained with different combinations of AR-C69931MX and MRS2179.Inhibition of thrombin-induced platelet activation (2 nM) with combinations of AR-C69931MX and the thrombin inhibitor melagatran did also result in a strong synergistic effect.To our knowledge, this is the first time that data supporting a synergistic effect has been published for the inhibitor combinations described.Whether this synergistic effect in vitro also results in an improved antithrombotic effect in vivo with or without an increased risk of bleeding remains to be studied in well-conducted clinical studies. PMID:15265806

  5. Profil Ekspresi mRNA Gen Murine Double Minute2, Kruppel-Like Factor4, dan c-Myc pada Fibrosarkoma

    Directory of Open Access Journals (Sweden)

    - Humaryanto

    2017-02-01

    Full Text Available Abstrak Fibrosarkoma hanya terjadi 1–3% dari seluruh keganasan jaringan lunak. Hingga saat ini etiologi fibrosarkoma belum diketahui dengan pasti. Beberapa faktor dapat menjadi penyebab patogenesis fibrosarkoma antara lain radiasi, terpapar zat kimia tertentu, serta infeksi human herpes virus 8 (HHV8 dan Epstein-Barr virus (EBV. Penelitian terkini menunjukkan bahwa banyak sarkoma terkait dengan mutasi genetik. Penelitian ini bertujuan melihat profil ekspresi mRNA gen Krüppel-like Factor4, Murine Double Minute2, dan c-Myc pada fibrosarkoma menggunakan teknik real time PCR kuantitatif (quantitative real time PCR, qRT-PCR. Analisis data menggunakan metode kuantititatif relatif 2-ΔΔCt. Penelitian ini menggunakan 10 sampel kasus fibrosarkoma yang ditemukan di Kota Jambi dari tahun 2011–2015. Hasil ΔCt (+SD MDM2, KLF-4, dan c-Myc disusun dari nilai yang terkecil hingga tertinggi adalah 1,85±2,14; 2,06±3,86; 2,9±2,66 secara berurutan. Dibanding dengan level ekspresi dengan GAPDH sebagai housekeeping gene, gen MDM2 dan KLF-4 relatif menurun dua kali lipat, sedangkan gen c-Myc relatif menurun lebih dari tiga kali lipat. Simpulan, penelitian ini menunjukkan bahwa pada kasus fibrosarkoma, gen c-Myc disupresi lebih kuat dibanding dengan gen MDM2 dan KLF-4. Abstract Fibrosarcoma is a rare soft tissue sarcoma, reported only 1–3% of all soft tissue sarcomas. Like any other soft-tissue sarcomas the definitive caused has not yet understood. Recognized causes include exposure to ionizing radiation, various physical and chemical factors, infection with human herpes virus (HHV8 and Epstein-Barr virus (EBV. Current research indicates many sarcomas are associated with genetic mutations. In this study, we investigated profile of mRNA gene expression KLF4, MDM2, and c-Myc of RNA in fibrosarcoma cases. The genes expression was examined using quantitative real time PCR (qRT-PCR and we analyzed the relative gene expression using the 2-ΔΔCt method. Ten

  6. Targeting C-Myc Promoter: Helquats As Novel G-Quadruplex Stabilizing Ligands

    Czech Academy of Sciences Publication Activity Database

    Kužmová, Erika; Kozák, Jaroslav; Komárková, Veronika; Pytlík, R.; Teplý, Filip; Hájek, Miroslav

    2014-01-01

    Roč. 124, č. 21 (2014) ISSN 0006-4971. [Annual Meeting of the American Society of Hematology /56./. 06.12.2014-09.12.2014, San Francisco] Institutional support: RVO:61388963 Keywords : helquats * C-Myc * leukemia Subject RIV: CE - Biochemistry

  7. Aberrant immunoglobulin and c-myc gene rearrangements in patients with nonmalignant monoclonal cryoglobulinemia

    International Nuclear Information System (INIS)

    Perl, A.; Wang, N.; Williams, J.M.; Hunt, M.J.; Rosenfeld, S.I.; Condemi, J.J.; Packman, C.H.; Abraham, G.N.

    1987-01-01

    The status of the immunoglobulin (Ig) genes was investigated in patients with idiopathic nonmalignant monoclonal IgG cryoglobulinemia (NCG). In NCG, monoclonal antibodies are synthesized at an accelerated rate by nonmalignant B lymphocytes. In order to determine whether this high production rate is related to a clonal B cell expansion, the rearrangement of the Ig genes was investigated by Southern blot analysis of genomic, 32 P-labelled, DNA extracted from the peripheral blood lymphocytes of four NCG patients. In three of four (VI, BR, and CH) clonal expansion of B cells was detected using probes specific for the genes. BamHI digestion of DNA from VI and BR produced three rearranged fragments which cohybridized with two of the probes. This finding suggested the presence of additional nonsecretory B cell clones and/or disruption of the gene segments spanned by and detected with the probes. In addition, the possibility of aberrant gene rearrangements was supported by noting the alteration of the c-myc gene locus in genomic DNA from peripheral blood leukocytes of VI and CH. Northern blot analysis of RNA isolated from peripheral blood B cells of VI and CH demonstrated aberrant transcripts of the c-myc gene, showing an active role of the altered c-myc locus. Detection of c-myc rearrangement in NCG patients clearly shows that this event may not be a final step in malignant B cell transformation

  8. ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

    Science.gov (United States)

    Kanamarlapudi, Venkateswarlu; Owens, Sian E; Saha, Keya; Pope, Robert J; Mundell, Stuart J

    2012-01-01

    Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1) and P2Y(12) purinoceptors. Recently, we demonstrated that P2Y(1) and P2Y(12) purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6) in the internalization and function of P2Y(1) and P2Y(12) purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1) or P2Y(12) purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP) kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

  9. ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

    Directory of Open Access Journals (Sweden)

    Venkateswarlu Kanamarlapudi

    Full Text Available Adenosine diphosphate (ADP is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1 and P2Y(12 purinoceptors. Recently, we demonstrated that P2Y(1 and P2Y(12 purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6 in the internalization and function of P2Y(1 and P2Y(12 purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1 or P2Y(12 purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

  10. Oncogenic c-Myc-induced lymphomagenesis is inhibited non-redundantly by the p19Arf–Mdm2–p53 and RP–Mdm2–p53 pathways

    OpenAIRE

    Meng, X; Carlson, NR; Dong, J; Zhang, Y

    2015-01-01

    The multifaceted oncogene c-Myc plays important roles in the development and progression of human cancer. Recent in vitro and in vivo studies have shown that the p19Arf–Mdm2–p53 and the ribosomal protein (RP)–Mdm2–p53 pathways are both essential in preventing oncogenic c-Myc-induced tumorigenesis. Disruption of each pathway individually by p19Arf deletion or by Mdm2C305F mutation, which disrupts RP-Mdm2 binding, accelerates Eμ-myc transgene-induced pre-B/B-cell lymphoma in mice at seemingly s...

  11. Inhibition of c-Myc overcomes cytotoxic drug resistance in acute myeloid leukemia cells by promoting differentiation.

    Directory of Open Access Journals (Sweden)

    Xiao-Na Pan

    Full Text Available Nowadays, drug resistance still represents a major obstacle to successful acute myeloid leukemia (AML treatment and the underlying mechanism is not fully elucidated. Here, we found that high expression of c-Myc was one of the cytogenetic characteristics in the drug-resistant leukemic cells. c-Myc over-expression in leukemic cells induced resistance to chemotherapeutic drugs, enhanced colony formation capacity and inhibited cell differentiation induced by all-trans retinoic acid (ATRA. Meanwhile, inhibition of c-Myc by shRNA or specific c-Myc inhibitor 10058-F4 rescued the sensitivity to cytotoxic drugs, restrained the colony formation ability and promoted differentiation. RT-PCR and western blotting analysis showed that down-regulation of C/EBPβ contributed to the poor differentiation state of leukemic cells induced by c-Myc over-expression. Importantly, over-expression of C/EBPβ could reverse c-Myc induced drug resistance. In primary AML cells, the c-Myc expression was negatively correlated with C/EBPβ. 10058-F4, displayed anti-proliferative activity and increased cellular differentiation with up-regulation of C/EBPβ in primary AML cells. Thus, our study indicated that c-Myc could be a novel target to overcome drug resistance, providing a new approach in AML therapy.

  12. Cytotoxic effect of γ-sitosterol from Kejibeling (Strobilanthes crispus and its mechanism of action towards c-myc gene expression and apoptotic pathway

    Directory of Open Access Journals (Sweden)

    Susi Endrini

    2015-01-01

    Full Text Available Background: This study aimed to analyze the cytotoxicity effect of γ-sitosterol isolated from “Kejibeling” (Strobilanthes crispus, a medicinal plant, on several cancer cell lines. The mechanisms of the effects were studied through the expression of cancer-caused gene, c-myc and apoptotic pathways.Methods: This in vitro study was done using human colon cancer cell lines (Caco-2, liver cancer cell lines (HepG2, hormone-dependent breast cancer cell lines (MCF-7 and the normal liver cell lines (Chang Liver. The cytotoxic effect was measured through MTT assay and the potential cytotoxic value was calculated by determining the toxic concentration which may kill up to 50% of the total cell used (IC50. Meanwhile, the cytotoxic mechanism was studied by determining the effect of adding γ-sitosterol to the c-myc gene expression by reverse transciptase-polymerase chain reaction (RT-PCR. The effect of γ-sitosterol through apoptotic pathway was studied by using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL assay.Results: γ-sitosterol was cytotoxic against Caco-2, HepG2, and MCF-7 with IC50-values of 8.3, 21.8, and 28.8 μg/mL, respectively. There were no IC50-values obtained from this compound against Chang Liver cell line. This compound induced apotosis on Caco-2 and HepG2 cell lines and suppressed the c-myc genes expression in both cells.Conclusion: γ-sitosterol was cytotoxic against colon and liver cancer cell lines and the effect was mediated by down-regulation of c-myc expression and induction of the apoptotic pathways.

  13. Sodium arsenite alters cell cycle and MTHFR, MT1/2, and c-Myc protein levels in MCF-7 cells

    International Nuclear Information System (INIS)

    Ruiz-Ramos, Ruben; Lopez-Carrillo, Lizbeth; Albores, Arnulfo; Hernandez-Ramirez, Raul U.; Cebrian, Mariano E.

    2009-01-01

    There is limited available information on the effects of arsenic on enzymes participating in the folate cycle. Therefore, our aim was to evaluate the effects of sodium arsenite on the protein levels of methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) and its further relationship with the expression MT1/2 and c-myc in MCF-7 cells. Arsenite treatment (0-10 μM) for 4 h decreased MTHFR levels in a concentration-dependent fashion without significant effects on DHFR. The effects on MTHFR were observed at arsenite concentrations not significantly affecting cell viability. We also observed an increase in S-phase recruitment at all concentrations probed. Lower concentrations (< 5 μM) induced cell proliferation, showing a high proportion of BrdU-stained cells, indicating a higher DNA synthesis rate. However, higher concentrations (≥ 5 μM) or longer treatment periods induced apoptosis. Arsenite also induced dose-dependent increases in MT1/2 and c-Myc protein levels. The levels of MTHFR were inversely correlated to MT1/2 and c-Myc overexpression and increased S-phase recruitment. Our findings indicate that breast epithelial cells are responsive to arsenite and suggest that exposure may pose a risk for breast cancer. The reductions in MTHFR protein levels contribute to understand the mechanisms underlying the induction of genes influencing growth regulation, such as c-myc and MT1/2. However, further research is needed to ascertain if the effects here reported following short-time and high-dose exposure are relevant for human populations chronically exposed to low arsenic concentrations.

  14. Aspirin therapy reduces the ability of platelets to promote colon and pancreatic cancer cell proliferation: Implications for the oncoprotein c-MYC

    Science.gov (United States)

    Sylman, Joanna L.; Ngo, Anh T. P.; Pang, Jiaqing; Sears, Rosalie C.; Williams, Craig D.; McCarty, Owen J. T.

    2017-01-01

    Aspirin, an anti-inflammatory and antithrombotic drug, has become the focus of intense research as a potential anticancer agent owing to its ability to reduce tumor proliferation in vitro and to prevent tumorigenesis in patients. Studies have found an anticancer effect of aspirin when used in low, antiplatelet doses. However, the mechanisms through which low-dose aspirin works are poorly understood. In this study, we aimed to determine the effect of aspirin on the cross talk between platelets and cancer cells. For our study, we used two colon cancer cell lines isolated from the same donor but characterized by different metastatic potential, SW480 (nonmetastatic) and SW620 (metastatic) cancer cells, and a pancreatic cancer cell line, PANC-1 (nonmetastatic). We found that SW480 and PANC-1 cancer cell proliferation was potentiated by human platelets in a manner dependent on the upregulation and activation of the oncoprotein c-MYC. The ability of platelets to upregulate c-MYC and cancer cell proliferation was reversed by an antiplatelet concentration of aspirin. In conclusion, we show for the first time that inhibition of platelets by aspirin can affect their ability to induce cancer cell proliferation through the modulation of the c-MYC oncoprotein. PMID:27903583

  15. Overexpression and amplification of the c-myc gene in mouse tumors induced by chemical and radiations

    Energy Technology Data Exchange (ETDEWEB)

    Niwa, Ohtsura; Enoki, Yoshitaka; Yokoro, Kenjiro

    1989-03-01

    We examined expression of the c-myc gene by the dot blot hybridization of total cellular RNA from mouse primary tumors induced by chemicals and radiations. Expression of the c-myc gene was found to be elevated in 69 cases among 177 independently induced tumors of 12 different types. DNA from tumors overexpressing the myc gene was analyzed by Southern blotting. No case of rearrangement was detected. However, amplification of the c-myc gene was found in 7 cases of primary sarcomas. These included 4 cases out of 24 methylcholanthrene-induced sarcomas and 3 cases out of 7 /alpha/-tocopherol-induced sacromas. We also analyzed 8 cases of sarcomas induced by radiations, but could not find changes in the gene structure of the c-myc gene. Thus, our data indicate tumor type specificity and agent specificity of c-myc gene amplification. (author).

  16. Ku70 acetylation and modulation of c-Myc/ATF4/CHOP signaling axis by SIRT1 inhibition lead to sensitization of HepG2 cells to TRAIL through induction of DR5 and down-regulation of c-FLIP

    DEFF Research Database (Denmark)

    Kim, Mi-Ju; Hong, Kyung-Soo; Kim, Hak-Bong

    2013-01-01

    In this study, we investigated the role of c-Myc/ATF4/CHOP signaling pathway in sensitization of human hepatoma HepG2 cells to TRAIL. Knockdown of SIRT1 or treatment with SIRT1 inhibitor caused the up-regulation of DR5 and down-regulation of c-FLIP through modulation of c-Myc/ATF4/CHOP pathway, a...

  17. c-Myc over-expression in Ramos Burkitt's lymphoma cell line predisposes to iron homeostasis disruption in vitro

    International Nuclear Information System (INIS)

    Habel, Marie-Eve; Jung, Daniel

    2006-01-01

    Burkitt's lymphoma is an aggressive B-cell neoplasm resulting from deregulated c-myc expression. We have previously shown that proliferation of Burkitt's lymphoma cell lines such as Ramos is markedly reduced by iron treatment. It has been shown that iron induces expression of c-myc which, owing to its transcriptional regulatory functions, regulates genes involved in iron metabolism. Transient enhancement of c-myc expression by iron could increase the expression of genes involved in iron incorporation, which could lead to an accumulation of intracellular free iron. Here, we have investigated whether cells with a high basal level of c-Myc were more likely to accumulate free iron. Our results suggest that the basal level of c-Myc in Ramos cells is twofold higher than what is seen in HL-60 cells. Moreover, in Ramos cells, where c-Myc is expressed at a high level, H-ferritin expression is down-regulated, transferrin receptor (CD71) expression is increased, and ferritin translation is inhibited. These modifications in iron metabolism, resulting from the strong basal expression of c-Myc, and amplified by iron addition, could lead to a disruption in homeostasis and consequently to growth arrest

  18. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    International Nuclear Information System (INIS)

    Yoshida, Go J.; Saya, Hideyuki

    2014-01-01

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 high / Fbw7 high / c-Myc low and proliferative cancer stem-like cells with CD44v8-10 high / Fbw7 low / c-Myc high

  19. Inversed relationship between CD44 variant and c-Myc due to oxidative stress-induced canonical Wnt activation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Go J., E-mail: medical21go@yahoo.co.jp; Saya, Hideyuki

    2014-01-10

    Highlights: •CD44 variant8–10 and c-Myc are inversely expressed in gastric cancer cells. •Redox-stress enhances c-Myc expression via canonical Wnt signal. •CD44v, but not CD44 standard, suppresses redox stress-induced Wnt activation. •CD44v expression promotes both transcription and proteasome degradation of c-Myc. •Inversed expression pattern between CD44v and c-Myc is often recognized in vivo. -- Abstract: Cancer stem-like cells express high amount of CD44 variant8-10 which protects cancer cells from redox stress. We have demonstrated by immunohistochemical analysis and Western blotting, and reverse-transcription polymerase chain reaction, that CD44 variant8-10 and c-Myc tend to show the inversed expression manner in gastric cancer cells. That is attributable to the oxidative stress-induced canonical Wnt activation, and furthermore, the up-regulation of the downstream molecules, one of which is oncogenic c-Myc, is not easily to occur in CD44 variant-positive cancer cells. We have also found out that CD44v8-10 expression is associated with the turn-over of the c-Myc with the experiments using gastric cancer cell lines. This cannot be simply explained by the model of oxidative stress-induced Wnt activation. CD44v8-10-positive cancer cells are enriched at the invasive front. Tumor tissue at the invasive area is considered to be composed of heterogeneous cellular population; dormant cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup high}/ c-Myc {sup low} and proliferative cancer stem-like cells with CD44v8-10 {sup high}/ Fbw7 {sup low}/ c-Myc {sup high}.

  20. Expression, purification, crystallization and structure of human adipocyte lipid-binding protein (aP2)

    International Nuclear Information System (INIS)

    Marr, Eric; Tardie, Mark; Carty, Maynard; Brown Phillips, Tracy; Wang, Ing-Kae; Soeller, Walt; Qiu, Xiayang; Karam, George

    2006-01-01

    The crystal structure of human adipocyte lipid-binding protein (aP2) with a bound palmitate is reported at 1.5 Å resolution. Human adipocyte lipid-binding protein (aP2) belongs to a family of intracellular lipid-binding proteins involved in the transport and storage of lipids. Here, the crystal structure of human aP2 with a bound palmitate is described at 1.5 Å resolution. Unlike the known crystal structure of murine aP2 in complex with palmitate, this structure shows that the fatty acid is in a folded conformation and that the loop containing Phe57 acts as a lid to regulate ligand binding by excluding solvent exposure to the central binding cavity

  1. A novel form of the RelA nuclear factor kappaB subunit is induced by and forms a complex with the proto-oncogene c-Myc.

    Science.gov (United States)

    Chapman, Neil R; Webster, Gill A; Gillespie, Peter J; Wilson, Brian J; Crouch, Dorothy H; Perkins, Neil D

    2002-01-01

    Members of both Myc and nuclear factor kappaB (NF-kappaB) families of transcription factors are found overexpressed or inappropriately activated in many forms of human cancer. Furthermore, NF-kappaB can induce c-Myc gene expression, suggesting that the activities of these factors are functionally linked. We have discovered that both c-Myc and v-Myc can induce a previously undescribed, truncated form of the RelA(p65) NF-kappaB subunit, RelA(p37). RelA(p37) encodes the N-terminal DNA binding and dimerization domain of RelA(p65) and would be expected to function as a trans-dominant negative inhibitor of NF-kappaB. Surprisingly, we found that RelA(p37) no longer binds to kappaB elements. This result is explained, however, by the observation that RelA(p37), but not RelA(p65), forms a high-molecular-mass complex with c-Myc. These results demonstrate a previously unknown functional and physical interaction between RelA and c-Myc with many significant implications for our understanding of the role that both proteins play in the molecular events underlying tumourigenesis. PMID:12027803

  2. Localization of P2X receptor subtypes 2, 3 and 7 in human urinary bladder.

    Science.gov (United States)

    Svennersten, Karl; Hallén-Grufman, Katarina; de Verdier, Petra J; Wiklund, N Peter; Poljakovic, Mirjana

    2015-08-08

    Voiding dysfunctions are a common problem that has a severe negative impact on the quality of life. Today there is a need for new drug targets for these conditions. The role of ATP receptors in bladder physiology has been studied for some time, primarily in animal models. The aim of this work is to investigate the localization of the ATP receptors P2X2, P2X3 and P2X7 and their colocalization with vimentin and actin in the human urinary bladder. Immunohistochemical analysis was conducted on full-thickness bladder tissues from fundus and trigonum collected from 15 patients undergoing open radical cystectomy due to chronic cystitis, bladder cancer or locally advanced prostate cancer. Colocalization analyses were performed between the three different P2X subtypes and the structural proteins vimentin and actin. Specimens were examined using epifluorescence microscopy and correlation coefficients were calculated for each costaining as well as the mean distance from the laminin positive basal side of the urothelium to the vimentin positive cells located in the suburothelium. P2X2 was expressed in vimentin positive cells located in the suburothelium. Less distinct labelling of P2X2 was also observed in actin positive smooth muscle cells and in the urothelium. P2X3 was expressed in vimentin positive cells surrounding the smooth muscle, and in vimentin positive cells located in the suburothelium. Weaker P2X3 labelling was seen in the urothelium. P2X7 was expressed in the smooth muscle cells and the urothelium. In the suburothelium, cells double positive for P2X2 and vimentin where located closer to the urothelium while cells double positive for P2X3 and vimentin where located further from the urothelium. The results from this study demonstrate that there is a significant difference in the expression of the purinergic P2X2, P2X3 and P2X7 receptors in the different histological layers of the human urinary bladder.

  3. Histopathological and molecular prognostic markers in medulloblastoma: c-myc, N-myc, TrkC, and anaplasia.

    Science.gov (United States)

    Eberhart, Charles G; Kratz, John; Wang, Yunyue; Summers, Krista; Stearns, Duncan; Cohen, Kenneth; Dang, Chi V; Burger, Peter C

    2004-05-01

    Several molecular and histopathological prognostic markers have been proposed for the therapeutic stratification of medulloblastoma patients. Amplification of the c-myc oncogene, elevated levels of c-myc mRNA, or tumor anaplasia have been associated with worse clinical outcomes. In contrast, high TrkC mRNA expression generally presages longer survival. The goal of this study was to evaluate the prognostic value of c-myc, N-myc and TrkC expression in medulloblastomas and compare them to histopathological classification. We used in situ hybridization to measure expression of these molecular markers. c-myc mRNA was detected in 18 of 59 (31%) cases, and was significantly associated with shorter patient survival times on both univariate and multivariate analyses (p = 0.04). The presence of c-myc mRNA was also significantly associated with tumor anaplasia. While survival rates were higher for patients with low N-myc or high TrkC expression, these differences were not statistically significant. The group of patients with either moderate or severely anaplastic tumors showed only a trend towards shorter survival (p = 0.11). However, severe anaplasia alone was significantly prognostic (p = 0.002). Given the prognostic import of c-myc, we investigated 2 potential mechanisms by which its expression might be regulated: Wnt signaling and Mxi-1 mutation. Nuclear translocation of beta-catenin, a marker of Wnt pathway activation, was more common in medulloblastomas with high c-myc than in tumors overall, but the difference was not statistically significant. No Mxi-1 mutations were detected in the 22 cases examined. The association we describe between c-myc expression, tumor anaplasia, and worse clinical outcomes provides further evidence for the importance of this oncogene in medulloblastoma pathobiology.

  4. Distribution of C-myc Antisense Oligonucleotides in Rabbits after Local Delivery by Implanted Gelatin Coated Piatinium -iridium Stent

    Institute of Scientific and Technical Information of China (English)

    张新霞; 庞志功; 崔长琮; 许香广; 胡雪松; 方卫华

    2003-01-01

    Objectives To assess the feasibility, efficiency and tissue distribution of localdelivered c - myc antisense oligonucleotides (ASODN)by implanted gelatin coated Platinium- Iridium (Pt-Ir) stent. Methods Gelatin coated Pt- Ir stentwhich absorbed carboxyfluorescein - 5 - succimidylester (FAM) labeled c -myc ASODN were implantedin the right carotid arteries of 6 rabbits under vision.Blood samples were collected at the indicated times.The target artery、 left carotid artery、 heart、 liver andkidney obtained at 45 minutes、 2 hours and 6hours. The concentration of c - myc ASODN in plasmaand tissues were determined by Thin Layer Fluorome-try. Tissue distribution of c- myc ASODN were as-sessed by fluorescence microscopy. Results At 45min, 2 h, 6 h, the concentration of FAM labeled c -myc ASODN in target artery was 244.39, 194.44,126.94(μg/g tissues) respectively, and the deliveryefficiency were 44.4% 、 35.4% and 23.1% respec-tively. At the same indicated time point, the plasmaconcentration was 8.41, 5. 83, 14.75 (μg/ml) respec-tively. Therefore c -myc ASODN concentrations in thetarget vessel were 29、 33 and 9 -fold higher than thatin the plasma. There was circumferential distribution oflabeled c -myc in the area of highest fluorescein co-inciding with the site of medial dissecting from stent-ing, and the label was most intense in target vesselmedia harvested at 45 min time point and then dis-persed to adventitia. Conclusions Gelatin coated Pt- Ir stent mediated local delivery of c - myc ASODN isfeasible and efficient. The localization of ASODN ismainly in target vessel wall.

  5. c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks.

    Science.gov (United States)

    Barfeld, Stefan J; Urbanucci, Alfonso; Itkonen, Harri M; Fazli, Ladan; Hicks, Jessica L; Thiede, Bernd; Rennie, Paul S; Yegnasubramanian, Srinivasan; DeMarzo, Angelo M; Mills, Ian G

    2017-04-01

    Prostate cancer (PCa) is the most common non-cutaneous cancer in men. The androgen receptor (AR), a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signaling networks have been shown to be altered in patients and to influence AR activity. Amongst these, the oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies and elevated protein levels of c-Myc are commonly observed in PCa. Its impact on AR activity, however, remains elusive. In this study, we assessed the impact of c-Myc overexpression on AR activity and transcriptional output in a PCa cell line model and validated the antagonistic effect of c-MYC on AR-targets in patient samples. We found that c-Myc overexpression partially reprogrammed AR chromatin occupancy and was associated with altered histone marks distribution, most notably H3K4me1 and H3K27me3. We found c-Myc and the AR co-occupy a substantial number of binding sites and these exhibited enhancer-like characteristics. Interestingly, c-Myc overexpression antagonised clinically relevant AR target genes. Therefore, as an example, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 (alias PSA, prostate specific antigen), and Glycine N-Methyltransferase (GNMT), in patient samples. Our findings provide unbiased evidence that MYC overexpression deregulates the AR transcriptional program, which is thought to be a driving force in PCa. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  6. c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks

    Directory of Open Access Journals (Sweden)

    Stefan J. Barfeld

    2017-04-01

    Full Text Available Prostate cancer (PCa is the most common non-cutaneous cancer in men. The androgen receptor (AR, a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signaling networks have been shown to be altered in patients and to influence AR activity. Amongst these, the oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies and elevated protein levels of c-Myc are commonly observed in PCa. Its impact on AR activity, however, remains elusive. In this study, we assessed the impact of c-Myc overexpression on AR activity and transcriptional output in a PCa cell line model and validated the antagonistic effect of c-MYC on AR-targets in patient samples. We found that c-Myc overexpression partially reprogrammed AR chromatin occupancy and was associated with altered histone marks distribution, most notably H3K4me1 and H3K27me3. We found c-Myc and the AR co-occupy a substantial number of binding sites and these exhibited enhancer-like characteristics. Interestingly, c-Myc overexpression antagonised clinically relevant AR target genes. Therefore, as an example, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 (alias PSA, prostate specific antigen, and Glycine N-Methyltransferase (GNMT, in patient samples. Our findings provide unbiased evidence that MYC overexpression deregulates the AR transcriptional program, which is thought to be a driving force in PCa.

  7. Expression of p27 and c-Myc by immunohistochemistry in breast ductal cancers in African American women.

    Science.gov (United States)

    Khan, Farhan; Ricks-Santi, Luisel J; Zafar, Rabia; Kanaan, Yasmine; Naab, Tammey

    2018-06-01

    Proteins p27 and c-Myc are both key players in the cell cycle. While p27, a tumor suppressor, inhibits progression from G1 to S phase, c-Myc, a proto-oncogene, plays a key role in cell cycle regulation and apoptosis. The objective of our study was to determine the association between expression of c-Myc and the loss of p27 by immunohistochemistry (IHC) in the four major subtypes of breast cancer (BC) (Luminal A, Luminal B, HER2, and Triple Negative) and with other clinicopathological factors in a population of 202 African-American (AA) women. Tissue microarrays (TMAs) were constructed from FFPE tumor blocks from primary ductal breast carcinomas in 202 AA women. Five micrometer sections were stained with a mouse monoclonal antibody against p27 and a rabbit monoclonal antibody against c-Myc. The sections were evaluated for intensity of nuclear reactivity (1-3) and percentage of reactive cells; an H-score was derived from the product of these measurements. Loss of p27 expression and c-Myc overexpression showed statistical significance with ER negative (p c-Myc expression/p27 loss and luminal A/B and Her2 overexpressing subtypes. In our study, a statistically significant association between c-Myc expression and p27 loss and the triple negative breast cancers (TNBC) was found in AA women. A recent study found that constitutive c-Myc expression is associated with inactivation of the axin 1 tumor suppressor gene. p27 inhibits cyclin dependent kinase2/cyclin A/E complex formation. Axin 1 and CDK inhibitors may represent possible therapeutic targets for TNBC. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Evaluation of the antitumor effects of c-Myc-Max heterodimerization inhibitor 100258-F4 in ovarian cancer cells.

    Science.gov (United States)

    Wang, Jiandong; Ma, Xiaoli; Jones, Hannah M; Chan, Leo Li-Ying; Song, Fang; Zhang, Weiyuan; Bae-Jump, Victoria L; Zhou, Chunxiao

    2014-08-21

    Epithelial ovarian carcinoma is the most lethal gynecological cancer due to its silent onset and recurrence with resistance to chemotherapy. Overexpression of oncogene c-Myc is one of the most frequently encountered events present in ovarian carcinoma. Disrupting the function of c-Myc and its downstream target genes is a promising strategy for cancer therapy. Our objective was to evaluate the potential effects of small-molecule c-Myc inhibitor, 10058-F4, on ovarian carcinoma cells and the underlying mechanisms by which 10058-F4 exerts its actions. Using MTT assay, colony formation, flow cytometry and Annexin V FITC assays, we found that 10058-F4 significantly inhibited cell proliferation of both SKOV3 and Hey ovarian cancer cells in a dose dependent manner through induction of apoptosis and cell cycle G1 arrest. Treatment with 10058-F4 reduced cellular ATP production and ROS levels in SKOV3 and Hey cells. Consistently, primary cultures of ovarian cancer treated with 10058-F4 showed induction of caspase-3 activity and inhibition of cell proliferation in 15 of 18 cases. The response to 10058-F4 was independent the level of c-Myc protein over-expression in primary cultures of ovarian carcinoma. These novel findings suggest that the growth of ovarian cancer cells is dependent upon c-MYC activity and that targeting c-Myc-Max heterodimerization could be a potential therapeutic strategy for ovarian cancer.

  9. Liver tumor formation by a mutant retinoblastoma protein in the transgenic mice is caused by an upregulation of c-Myc target genes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bo; Hikosaka, Keisuke; Sultana, Nishat; Sharkar, Mohammad Tofael Kabir [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Noritake, Hidenao [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Kimura, Wataru; Wu, Yi-Xin [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Kobayashi, Yoshimasa [Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Uezato, Tadayoshi [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan); Miura, Naoyuki, E-mail: nmiura@hama-med.ac.jp [Department of Biochemistry, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Higashi-ku, Hamamatsu 431-3192 (Japan)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Fifty percent of the mutant Rb transgenic mice produced liver tumors. Black-Right-Pointing-Pointer In the tumor, Foxm1, Skp2, Bmi1 and AP-1 mRNAs were up-regulated. Black-Right-Pointing-Pointer No increase in expression of the Myc-target genes was observed in the non-tumorous liver. Black-Right-Pointing-Pointer Tumor formation depends on up-regulation of the Myc-target genes. -- Abstract: The retinoblastoma (Rb) tumor suppressor encodes a nuclear phosphoprotein that regulates cellular proliferation, apoptosis and differentiation. In order to adapt itself to these biological functions, Rb is subjected to modification cycle, phosphorylation and dephosphorylation. To directly determine the effect of phosphorylation-resistant Rb on liver development and function, we generated transgenic mice expressing phosphorylation-resistant human mutant Rb (mt-Rb) under the control of the rat hepatocyte nuclear factor-1 gene promoter/enhancer. Expression of mt-Rb in the liver resulted in macroscopic neoplastic nodules (adenomas) with {approx}50% incidence within 15 months old. Interestingly, quantitative reverse transcriptase-PCR analysis showed that c-Myc was up-regulated in the liver of mt-Rb transgenic mice irrespective of having tumor tissues or no tumor. In tumor tissues, several c-Myc target genes, Foxm1, c-Jun, c-Fos, Bmi1 and Skp2, were also up-regulated dramatically. We determined whether mt-Rb activated the Myc promoter in the HTP9 cells and demonstrated that mt-Rb acted as an inhibitor of wild-type Rb-induced repression on the Myc promoter. Our results suggest that continued upregulation of c-Myc target genes promotes the liver tumor formation after about 1 year of age.

  10. Localisation of lung cancer by a radiolabelled monoclonal antibody against the c-myc oncogene product

    Energy Technology Data Exchange (ETDEWEB)

    Chan, S Y.T.; Evan, G I; Ritson, A; Watson, J; Wraight, P; Sikora, K

    1986-11-01

    A set of mouse monoclonal antibodies against the c-myc oncogene product, a 62,000 dalton nuclear binding protein involved in cell cycle control, has been constructed by immunisation with synthetic peptide fragments. One such antibody, CT14, was radiolabelled with /sup 131/I and administered to 20 patients with different malignant diseases. Good tumour localisation was observed in 12 out of 14 patients with primary bronchial carcinoma but not in patients with pulmonary metastases from primary tumours elsewhere. Successfully localised tumours were all 3 cm or more in diameter. Monoclonal antibodies against oncogene products may provide novel selective tools for the diagnosis and therapy of cancer.

  11. The effect of Glut1 and c-myc on prognosis in esophageal squamous cell carcinoma of Kazakh and Han patients.

    Science.gov (United States)

    Zhou, Ya-Xing; Zhou, Ke-Ming; Liu, Qian; Wang, Hui; Wang, Wen; Shi, Yi; Ma, Yu-Qing

    2018-04-09

    Glucose transporter type 1 (Glut1) plays a crucial role in cancer-specific metabolism. We explored the expression of Glut1 and c-myc, the relationship between them and the effect of Glut1, c-myc on prognosis in esophageal squamous cell carcinoma. Immunohistochemistry was used to examine the expression of Glut1 and c-myc. χ 2 test analyzes the relationship between c-myc, Glut1 and pathological parameters. Spearman correlation analyzes the relationship between c-myc and Glut1. Survival analysis was used to investigate the effect of Glut1 and c-myc on prognosis. Glut1 positivity was associated with tumor size (p C-myc positivity was associated with tumor location (p = 0.015), depth of invasion (p = 0.022) and lymph node metastasis (p = 0.035). There was a positive correlation between c-myc and Glut1 (r = 0.321). Patients with Glut1 c-myc co-expression had poorer prognosis. Inhibiting Glut1 c-myc co-expression may improve the prognosis of esophageal squamous cell carcinoma.

  12. Absence of DNA damage after 60-Hz electromagnetic field exposure combined with ionizing radiation, hydrogen peroxide, or c-Myc overexpression.

    Science.gov (United States)

    Jin, Yeung Bae; Choi, Seo-Hyun; Lee, Jae Seon; Kim, Jae-Kyung; Lee, Ju-Woon; Hong, Seung-Cheol; Myung, Sung Ho; Lee, Yun-Sil

    2014-03-01

    The principal objective of this study was to assess the DNA damage in a normal cell line system after exposure to 60 Hz of extremely low frequency magnetic field (ELF-MF) and particularly in combination with various external factors, via comet assays. NIH3T3 mouse fibroblast cells, WI-38 human lung fibroblast cells, L132 human lung epithelial cells, and MCF10A human mammary gland epithelial cells were exposed for 4 or 16 h to a 60-Hz, 1 mT uniform magnetic field in the presence or absence of ionizing radiation (IR, 1 Gy), H(2)O(2) (50 μM), or c-Myc oncogenic activation. The results obtained showed no significant differences between the cells exposed to ELF-MF alone and the unexposed cells. Moreover, no synergistic or additive effects were observed after 4 or 16 h of pre-exposure to 1 mT ELF-MF or simultaneous exposure to ELF-MF combined with IR, H(2)O(2), or c-Myc activation.

  13. Neutron scattering studies on protein dynamics using the human myelin peripheral membrane protein P2

    Directory of Open Access Journals (Sweden)

    Laulumaa Saara

    2015-01-01

    Full Text Available Myelin is a multilayered proteolipid membrane structure surrounding selected axons in the vertebrate nervous system, which allows the rapid saltatory conduction of nerve impulses. Deficits in myelin formation and maintenance may lead to chronic neurological disease. P2 is an abundant myelin protein from peripheral nerves, binding between two apposing lipid bilayers. We studied the dynamics of the human myelin protein P2 and its mutated P38G variant in hydrated powders using elastic incoherent neutron scattering. The local harmonic vibrations at low temperatures were very similar for both samples, but the mutant protein had increased flexibility and softness close to physiological temperatures. The results indicate that a drastic mutation of proline to glycine at a functional site can affect protein dynamics, and in the case of P2, they may explain functional differences between the two proteins.

  14. Neutron scattering studies on protein dynamics using the human myelin peripheral membrane protein P2

    Science.gov (United States)

    Laulumaa, Saara; Kursula, Petri; Natali, Francesca

    2015-01-01

    Myelin is a multilayered proteolipid membrane structure surrounding selected axons in the vertebrate nervous system, which allows the rapid saltatory conduction of nerve impulses. Deficits in myelin formation and maintenance may lead to chronic neurological disease. P2 is an abundant myelin protein from peripheral nerves, binding between two apposing lipid bilayers. We studied the dynamics of the human myelin protein P2 and its mutated P38G variant in hydrated powders using elastic incoherent neutron scattering. The local harmonic vibrations at low temperatures were very similar for both samples, but the mutant protein had increased flexibility and softness close to physiological temperatures. The results indicate that a drastic mutation of proline to glycine at a functional site can affect protein dynamics, and in the case of P2, they may explain functional differences between the two proteins.

  15. Relationship of Amplification and Expression of the C-MYC Gene with Survival among Gastric Cancer Patients.

    Science.gov (United States)

    Khaleghian, Malihea; Shakoori, Abbas; Razavi, Amirnader Emami; Azimi, Cyrus

    2015-01-01

    During the past decades, the incidence and mortality rate of stomach cancer has demonstrated a great decrease in the world, but it is still one of the most common and fatal cancers especially among men worldwide, including Iran. The MYC proto-oncogene, which is located at 8q24.1, regulates 15% of genes and is activated in 20% of all human tumors. MYC amplification and overexpression of its protein product has been reported in 15-30% of gastric neoplasias. The aim of this investigation was to find the relative efficacy of CISH (chromogenic in situ hybridization) or IHC (immunohistochemistry) in diagnosis and prognosis of gastric cancer, as well as the relationship of amplification and expression of C-MYC gene with patient survival. In this cross-sectional study, 102 samples of gastric cancer were collected from patients who had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences, from July 2009 to March 2014. All samples were randomly selected from those who were diagnosed with gastric adenocarcinomas. CISH and IHC methods were performed on all of them. Patients were classified into two groups. The first consisted of stage I and II cases, and the second of stage III and IV. Survival tests for both groups was carried out with referrnce to CISH test reults. Group II (stage III and IV) with CISH+ featured lower survival than those with CISH- (p=0.233), but group I (stage I and II) patients demonstrated no significant variation with CISH+ or CISH- (p=0.630). Kaplan-Meier for both groups was carried out with IHC test findings and showed similar results. This data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in men than women. Our data also showed that CISH+ patients (43%) were more frequent in comparison with IHC+ patients (14.7%). For planning treatment of gastric cancer patients, by focusing on expanding tumors, which is the greatest concern of the surgeons and

  16. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    International Nuclear Information System (INIS)

    Han, Yu; Zhong, Cuiping; Hong, Liu; Wang, Ye; Qiao, Li; Qiu, Jianhua

    2009-01-01

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  17. Effect of c-myc on the ultrastructural structure of cochleae in guinea pigs with noise induced hearing loss

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yu; Zhong, Cuiping [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Hong, Liu [First Division of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Wang, Ye; Qiao, Li [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China); Qiu, Jianhua, E-mail: qiujh@fmmu.edu.cn [Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 Shaanxi Province (China)

    2009-12-18

    Noise over-stimulation may induce hair cells loss and hearing deficit. The c-myc oncogene is a major regulator for cell proliferation, growth, and apoptosis. However, the role of this gene in the mammalian cochlea is still unclear. The study was designed to firstly investigate its function under noise condition, from the aspect of cochlear ultrastructural changes. We had established the adenoviral vector of c-myc gene and delivered the adenovirus suspension into the scala tympani of guinea pigs 4 days before noise exposure. The empty adenoviral vectors were injected as control. Then, all subjects were exposed to 4-kHz octave-band noise at 110 dB SPL for 8 h/day, 3 days consecutively. Auditory thresholds were assessed by auditory brainstem response, prior to and 7 days following noise exposure. On the seventh days after noise exposure, the cochlear sensory epithelia surface was observed microscopically and the cochleae were taken to study the ultrastructural changes. The results indicated that auditory threshold shift after noise exposure was higher in the ears treated with Ad.EGFP than that treated with Ad.c-myc-EGFP. Stereocilia loss and the disarrangement of outer hair cells were observed, with greater changes found in the Ad.EGFP group. Also, the ultrastructure changes were severe in the Ad.EGFP group, but not obvious in the Ad.c-myc-EGFP group. Therefore, c-myc gene might play an unexpected role in hearing functional and morphological protection from acoustic trauma.

  18. Hsa-let-7a functions as a tumor suppressor in renal cell carcinoma cell lines by targeting c-myc

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongchao; Yin, Bingde; Zhang, Changcun; Zhou, Libin [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China); Fan, Jie, E-mail: jief67@sina.com [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer This study is the first to test the let-7a/c-myc loop in renal cell carcinoma cell lines. Black-Right-Pointing-Pointer Let-7a down-regulated c-myc in three renal cell carcinoma cell lines. Black-Right-Pointing-Pointer c-myc target genes were down-regulated because of the let-7a-mediated down-regulation of c-myc. Black-Right-Pointing-Pointer The let-7a/c-myc loop has a significant function in renal cell carcinoma cell lines. -- Abstract: Widespread functions of the c-myc pathway play a crucial role in renal cell carcinoma (RCC) carcinogenesis. Thus, we evaluated the connection between proto-oncogenic c-myc and anti-neoplastic hsa-let-7a (let-7a) in RCC cell lines. The levels of c-myc and let-7a in 3 RCC cell lines (769P, Caki-1 and 786O) were measured after transfecting the cells with let-7a mimics or a negative control. The change in c-myc protein level was confirmed by Western blot. The anti-neoplastic function of let-7a was evaluated using cell counting kit-8 (CCK-8) for proliferation analysis and cell flow cytometry for cell cycle analysis. The changes of downstream targets of c-myc were measured using reverse transcription quantitative real-time PCR (qRT-PCR). Our results suggest for the first time that let-7a acts as a tumor suppressor in RCC cell lines by down-regulating c-myc and c-myc target genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1) and the miR17-92 cluster, which is accompanied by proliferation inhibition and cell cycle arrest.

  19. Expression Analysis of p16, c-Myc, and mSin3A in Non-small Cell Lung Cancer by Computer Aided Scoring and Analysis (CASA).

    Science.gov (United States)

    Salmaninejad, Arash; Estiar, Mehrdad Asghari; Gill, Rajbir K; Shih, Joanna H; Hewitt, Stephen; Jeon, Hyo-Sung; Fukuoka, Junya; Shilo, Konstantin; Shakoori, Abbas; Jen, Jin

    2015-01-01

    Immunohistochemical analysis (IHC) of tissue microarray (TMA) slides enables large sets of tissue samples to be analyzed simultaneously on a single slide. However, manual evaluation of small cores on a TMA slide is time consuming and error prone. We describe a computer aided scoring and analysis (CASA) method to allow facile and reliable scoring of IHC staining using TMA containing 300 non-small cell lung cancer (NSCLC) cases. In the two previous published papers utilizing our TMA slides of lung cancer we examined 18 proteins involved in the chromatin machinery. We developed our study using more proteins of the chromatin complex and several transcription factors that facilitate the chromatin machinery. Then, a total of 78 antibodies were evaluated by CASA to derive a normalized intensity value that correlated with the overall staining status of the targeting protein. The intensity values for TMA cores were then examined for association to clinical variables and predictive significance individually and with other factors. RESULTs: Using our TMA, the intensity of several protein pairs were significantly correlated with an increased risk of death in NSCLC. These included c-Myc with p16, mSin3A with p16 and c-Myc with mSinA. Predictive values of these pairs remained significant when evaluated based on standard IHC scores. Our results demonstrate the usefulness of CASA as a valuable tool for systematic assessment of TMA slides to identify potential predictive biomarkers using a large set of primary human tissues.

  20. EFFECT OF STENT ABSORBED c-myc ANTISENSE OLIGODEOXYNUCLEOTIDE ON SMOOTH MUSCLE CELLS APOPTOSIS IN RABBIT CAROTID ARTERY

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 李江; 崔翰斌; 徐仓宝; 朱参战

    2002-01-01

    Objective To investigate the effect of gelatin coated Platinium-Iridium stent absorbed c-myc antisense oligodeoxynucleotide (ASODN) on smooth muscle cells apoptosis in a normal rabbit carotid arteries. Methods Gelatin coated Platinium-Iridium stents were implanted in the right carotid arteries of 32 rabbits under vision. Animals were randomly divided into control group and treated group receiving c-myc ASODN (n=16, respectively). On 7, 14, 30 and 90 days following the stenting procedure ,morphometry for caculation of neointimal area and mean neointimal thickness were performed.The expression of c-myc protein was detected by immunohistochemical method. Apoptotic smooth muscle cells was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL). Results At 7 and 14 days after stenting,there were no detectable apoptotic cells in both groups. The apoptotic cells occurred in the neointima 30 and 90 days after stenting, and the number of apoptotic cells at 30 days were less [4.50±1.29 vs 25.75±1.89 (number/0.1mm2)] than that at 90 days [13.50±1.91 vs 41.50±6.46 (number/0.1mm2)]. Meanwhile c-myc ASODN induced more apoptotic cells than the control group(P<0.0001). c-myc protein expression was weak positive or negative in treated group and positive in control group.Conclusion c-myc ASODN can induce smooth muscle cells apoptosis after stenting in normal rabbit carotid arteries,and it can be used to prevent in-stent restenosis.

  1. c-Myc affects mRNA translation, cell proliferation and progenitor cell function in the mammary gland

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    Trumpp Andreas

    2009-09-01

    Full Text Available Abstract Background The oncoprotein c-Myc has been intensely studied in breast cancer and mouse mammary tumor models, but relatively little is known about the normal physiological role of c-Myc in the mammary gland. Here we investigated functions of c-Myc during mouse mammary gland development using a conditional knockout approach. Results Generation of c-mycfl/fl mice carrying the mammary gland-specific WAPiCre transgene resulted in c-Myc loss in alveolar epithelial cells starting in mid-pregnancy. Three major phenotypes were observed in glands of mutant mice. First, c-Myc-deficient alveolar cells had a slower proliferative response at the start of pregnancy, causing a delay but not a block of alveolar development. Second, while milk composition was comparable between wild type and mutant animals, milk production was reduced in mutant glands, leading to slower pup weight-gain. Electron microscopy and polysome fractionation revealed a general decrease in translational efficiency. Furthermore, analysis of mRNA distribution along the polysome gradient demonstrated that this effect was specific for mRNAs whose protein products are involved in milk synthesis. Moreover, quantitative reverse transcription-polymerase chain reaction analysis revealed decreased levels of ribosomal RNAs and ribosomal protein-encoding mRNAs in mutant glands. Third, using the mammary transplantation technique to functionally identify alveolar progenitor cells, we observed that the mutant epithelium has a reduced ability to repopulate the gland when transplanted into NOD/SCID recipients. Conclusion We have demonstrated that c-Myc plays multiple roles in the mouse mammary gland during pregnancy and lactation. c-Myc loss delayed, but did not block proliferation and differentiation in pregnancy. During lactation, lower levels of ribosomal RNAs and proteins were present and translation was generally decreased in mutant glands. Finally, the transplantation studies suggest a role

  2. The Max b-HLH-LZ can transduce into cells and inhibit c-Myc transcriptional activities.

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    Martin Montagne

    Full Text Available The inhibition of the functions of c-Myc (endogenous and oncogenic was recently shown to provide a spectacular therapeutic index in cancer mouse models, with complete tumor regression and minimal side-effects in normal tissues. This was achieved by the systemic and conditional expression of omomyc, the cDNA of a designed mutant of the b-HLH-LZ of c-Myc named Omomyc. The overall mode of action of Omomyc consists in the sequestration of Max and the concomitant competition of the Omomyc/Max complex with the endogenous c-Myc/Max heterodimer. This leads to the inhibition of the transactivation of Myc target genes involved in proliferation and metabolism. While this body of work has provided extraordinary insights to guide the future development of new cancer therapies that target c-Myc, Omomyc itself is not a therapeutic agent. In this context, we sought to exploit the use of a b-HLH-LZ to inhibit c-Myc in a cancer cell line in a more direct fashion. We demonstrate that the b-HLH-LZ domain of Max (Max* behaves as a bona fide protein transduction domain (PTD that can efficiently transduce across cellular membrane via through endocytosis and translocate to the nucleus. In addition, we show that the treatment of HeLa cells with Max* leads to a reduction of metabolism and proliferation rate. Accordingly, we observe a decrease of the population of HeLa cells in S phase, an accumulation in G1/G0 and the induction of apoptosis. In agreement with these phenotypic changes, we show by q-RT-PCR that the treatment of HeLa cells with Max* leads to the activation of the transcription c-Myc repressed genes as well as the repression of the expression of c-Myc activated genes. In addition to the novel discovery that the Max b-HLH-LZ is a PTD, our findings open up new avenues and strategies for the direct inhibition of c-Myc with b-HLH-LZ analogs.

  3. Transformation of follicular lymphoma to plasmablastic lymphoma with c-myc gene rearrangement.

    Science.gov (United States)

    Ouansafi, Ihsane; He, Bing; Fraser, Cory; Nie, Kui; Mathew, Susan; Bhanji, Rumina; Hoda, Rana; Arabadjief, Melissa; Knowles, Daniel; Cerutti, Andrea; Orazi, Attilio; Tam, Wayne

    2010-12-01

    Follicular lymphoma (FL) is an indolent lymphoma that transforms to high-grade lymphoma, mostly diffuse large B-cell lymphoma, in about a third of patients. We present the first report of a case of FL that transformed to plasmablastic lymphoma (PBL). Clonal transformation of the FL to PBL was evidenced by identical IGH/BCL2 gene rearrangements and VDJ gene usage in rearranged IGH genes. IGH/ BCL2 translocation was retained in the PBL, which also acquired c-myc gene rearrangement. Genealogic analysis based on somatic hypermutation of the rearranged IGH genes of both FL and PBL suggests that transformation of the FL to PBL occurred most likely by divergent evolution from a common progenitor cell rather than direct evolution from the FL clone. Our study of this unusual case expands the histologic spectrum of FL transformation and increases our understanding of the pathogenetic mechanisms of transformation of indolent lymphomas to aggressive lymphomas.

  4. Intercellular calcium signaling occurs between human osteoblasts and osteoclasts and requires activation of osteoclast P2X7 receptors

    DEFF Research Database (Denmark)

    Jørgensen, Niklas R; Henriksen, Zanne; Sørensen, Ole

    2002-01-01

    that human osteoclasts expressed functional P2Y1 receptors, but, unexpectedly, desensitization of P2Y1 did not block calcium signaling to osteoclasts. We also found that osteoclasts expressed functional P2X7 receptors and showed that pharmacological inhibition of these receptors blocked calcium signaling...

  5. Insertion of the LINE-1 element in the C-MYC gene and immunoreactivity of C-MYC, p53, p21 and p27 proteins in different morphological patterns of the canine TVT

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    C.R.O. Lima

    2016-06-01

    Full Text Available ABSTRACT The canine transmissible venereal tumor (TVT affects the external genitalia of dogs by the natural transplant of viable tumor cells. Thus, this research aimed to diagnose and characterize TVT morphological patterns, identify the insertion of the LINE-1 element in C-MYC gene, by means of the polymerase chain reaction (PCR, and evaluate the immunohistochemical expression of C-MYC, p53, p21 and p27 proteins. The relationship between C-MYC and p53 proteins and their interference on the expression of p21 and p27 were also studied. For that, 20 samples of naturally occurring TVT were used, subjected to cytopathological, histopathological and immunohistochemical analysis, and to molecular diagnosis of neoplasia. The increased tissue expression and the correlation among C-MYC, p53, p21 and p27 proteins indicate reduction and/or loss of their functionality in the TVT microenvironment, with consequent apoptotic suppression, maintenance of cell growth and progression of neoplasia.

  6. 3D view to tumor suppression: Lkb1, polarity and the arrest of oncogenic c-Myc.

    Science.gov (United States)

    Partanen, Johanna I; Nieminen, Anni I; Klefstrom, Juha

    2009-03-01

    Machiavelli wrote, in his famous political treatise Il Principe, about disrupting organization by planting seeds of dissension or by eliminating necessary support elements. Tumor cells do exactly that by disrupting the organized architecture of epithelial cell layers during progression from contained benign tumor to full-blown invasive cancer. However, it is still unclear whether tumor cells primarily break free by activating oncogenes powerful enough to cause chaos or by eliminating tumor suppressor genes guarding the order of the epithelial organization. Studies in Drosophila have exposed genes that encode key regulators of the epithelial apicobasal polarity and which, upon inactivation, cause disorganization of the epithelial layers and promote unscheduled cell proliferation. These polarity regulator/tumor suppressor proteins, which include products of neoplastic tumor suppressor genes (nTSGs), are carefully positioned in polarized epithelial cells to maintain the order of epithelial structures and to impose a restraint on cell proliferation. In this review, we have explored the presence and prevalence of somatic mutations in the human counterparts of Drosophila polarity regulator/tumor suppressor genes across the human cancers. The screen points out LKB1, which is a causal genetic lesion in Peutz-Jeghers cancer syndrome, a gene mutated in certain sporadic cancers and a human homologue of the fly polarity gene par-4. We review the evidence linking Lkb1 protein to polarity regulation in the scope of our recent results suggesting a coupled role for Lkb1 as an architect of organized acinar structures and a suppressor of oncogenic c-Myc. We finally present models to explain how Lkb1-dependent formation of epithelial architecture is coupled to suppression of normal and oncogene-induced proliferation.

  7. Disturbance of Bcl-2, Bax, Caspase-3, Ki-67 and C-myc expression in acute and subchronic exposure to benzo(a)pyrene in cervix.

    Science.gov (United States)

    Gao, Meili; Li, Yongfei; Ji, Xiaoying; Xue, Xiaochang; Chen, Lan; Feng, Guodong; Zhang, Huqin; Wang, Huichun; Shah, Walayat; Hou, Zhanwu; Kong, Yu

    2016-03-01

    Epidemiological studies have demonstrated that cigarette smoking is an important cofactor or an independent risk factor for the development of cervical cancer. Benzo(a)pyrene (BaP) is one of the most potent tobacco smoke carcinogens in tobacco smoke. BaP induced DNA damage and over expression in p53 cervical tissue of mice as demonstrated in our previous study. Here we present the findings of exposure to BaP on the expression of Bcl-2, C-myc, Ki-67, Caspase-3 and Bax genes in mouse cervix. Acute intraperitoneal administration of BaP (12.5, 25, 50, 100mg/kg body weight) to ICR female mice induced a significant increase in Bcl-2, C-myc, Ki-67 mRNA and protein level till 72h except in Bcl-2 at 24h with 12.5, 25, 50mg/kg as well as at 48h with 12.5mg/kg body weight post treatment. A significant increase was also seen in Caspase-3 and Bax mRNA and protein level with peak level at 24h and gradual decrease till 72h, however, the expression of caspase-3 increased while that of Bax decreased with increasing dose of Bap after 24h. In sub chronic intraperitoneal and oral gavage administration of BaP (2.5, 5, 10mg/kg body weight), similar significant increase was observed for all the examined genes as compared to the control and vehicle groups, however the expression of Bax decreased in a dose dependent manner. The findings of this study will help in further understanding the molecular mechanism of BaP induced carcinogenesis of cervical cancer. Copyright © 2015 Elsevier GmbH. All rights reserved.

  8. SirT1 confers hypoxia-induced radioresistance via the modulation of c-Myc stabilization on hepatoma cells

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    Xie Yuexia; Zhang Jianghong; Shao Chunlin; Xu Yanwu

    2012-01-01

    Intratumoral hypoxia is an important contributory factor to tumor cell resistance to radiotherapy. SirT1, a nicotinamide adenine dinucleotide (NAD + )-dependent histone/protein deacetylase, has been linked to the decrease of radiation-induced DNA damage and seems to be critical for cancer therapy. The purpose of this study was to investigate the role of SirT1 in hypoxia-induced radiation response on hepatoma cells. It was found that the administration with resveratrol, a putative SirT1 activator, enhanced the resistance of HepG2 cells against radiation-induced DNA damage of MN formation under hypoxia condition; while nicotinamide, a well-known SirT1 inhibitor, sensitized this radiation damage. Nevertheless, pretreatment of cells with 10058-F4, a specific inhibitor of c-Myc, almost eliminated the nicotinamide-induced radiosensitive effect. Further studies revealed that resveratrol inhibited c-Myc protein accumulation via up-regulation of SirT1 expression and deacetylase activity, and this loss of c-Myc protein was abolished by inhibiting its degradation in the presence of MG132, a potent inhibitor of proteasome. In contrast, nicotinamide attenuated c-Myc protein degradation induced by radiation under hypoxia through inhibition of SirT1 deacetylase activity. Our findings suggest that SirT1 could serve as a novel potent target of radiation-induced DNA damage and thus as a potential strategy to advance the efficiency of radiation therapy in hepatoma entities. (author)

  9. Nac1 promotes self-renewal of embryonic stem cells through direct transcriptional regulation of c-Myc.

    Science.gov (United States)

    Ruan, Yan; He, Jianrong; Wu, Wei; He, Ping; Tian, Yanping; Xiao, Lan; Liu, Gaoke; Wang, Jiali; Cheng, Yuda; Zhang, Shuo; Yang, Yi; Xiong, Jiaxiang; Zhao, Ke; Wan, Ying; Huang, He; Zhang, Junlei; Jian, Rui

    2017-07-18

    The pluripotency transcriptional network in embryonic stem cells (ESCs) is composed of distinct functional units including the core and Myc units. It is hoped that dissection of the cellular functions and interconnections of network factors will aid our understanding of ESC and cancer biology. Proteomic and genomic approaches have identified Nac1 as a member of the core pluripotency network. However, previous studies have predominantly focused on the role of Nac1 in psychomotor stimulant response and cancer pathogenesis. In this study, we report that Nac1 is a self-renewal promoting factor, but is not required for maintaining pluripotency of ESCs. Loss of function of Nac1 in ESCs results in a reduced proliferation rate and an enhanced differentiation propensity. Nac1 overexpression promotes ESC proliferation and delays ESC differentiation in the absence of leukemia inhibitory factor (LIF). Furthermore, we demonstrated that Nac1 directly binds to the c-Myc promoter and regulates c-Myc transcription. The study also revealed that the function of Nac1 in promoting ESC self-renewal appears to be partially mediated by c-Myc. These findings establish a functional link between the core and c-Myc-centered networks and provide new insights into mechanisms of stemness regulation in ESCs and cancer.

  10. Overexpression of c-myc is associated with adverse clinical features and worse overall survival in multiple myeloma

    DEFF Research Database (Denmark)

    Szabo, Agoston Gyula; Gang, Anne Ortved; Pedersen, Mette Ølgod

    2016-01-01

    The role of c-myc in multiple myeloma (MM) is controversial. We conducted a retrospective study of 117 patients with MM diagnosed between 2004 and 2010 at Herlev Hospital. Immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) were performed on tissue microarrays (TMAs) made from...

  11. c-Myc Enhances Sonic Hedgehog-Induced Medulloblastoma Formation from Nestin-Expressing Neural Progenitors in Mice

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    Ganesh Rao

    2003-05-01

    Full Text Available Medulloblastomas are malignant brain tumors that arise in the cerebella of children. The presumed cellsof-origin are undifferentiated precursors of granule neurons that occupy the external granule layer (EGL of the developing cerebellum. The overexpression of proteins that normally stimulate proliferation of neural progenitor cells may initiate medulloblastoma formation. Two known mitogens for neural progenitors are the c-Myc oncoprotein and Sonic hedgehog (Shh, a crucial determinant of embryonic pattern formation in the central nervous system. We modeled the ability of c-Myc and Shh to induce medulloblastoma in mice using the RCAS/tv-a system, which allows postnatal gene transfer and expression in a cell type-specific manner. We targeted the expression of Shh and c-Myc to nestin-expressing neural progenitor cells by injecting replication-competent ALV splice acceptor (RCAS vectors into the cerebella of newborn mice. Following injection with RCAS-Shh alone, 3/32 (9% mice developed medulloblastomas and 5/32 showed multifocal hyperproliferation of the EGL, possibly a precursor stage of medulloblastoma. Following injection with RCAS-Shh plus RCAS-Myc, 9/39 (23% mice developed medulloblastomas. We conclude that nestin-expressing neural progenitors, present in the cerebellum at birth, can act as the cells-of-origin for medulloblastoma, and that c-Myc cooperates with Shh to enhance tumorigenicity.

  12. TATA-binding protein and the retinoblastoma gene product bind to overlapping epitopes on c-Myc and adenovirus E1A protein

    NARCIS (Netherlands)

    Hateboer, G.; Timmers, H.T.M.; Rustgi, A.K.; Billaud, Marc; Veer, L.J. Van 't; Bernards, R.A.

    1993-01-01

    Using a protein binding assay, we show that the amino-teminal 204 amino acids of the c-Myc protein interact di y with a key component of the basal p tdon factor TFID, the TATA box-binding protein (TBP). Essentialy the same region of the c-Myc protein alo binds the product of the retinoblatoma

  13. Endoglin inhibits ERK-induced c-Myc and cyclin D1 expression to impede endothelial cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Christopher C.; Bloodworth, Jeffrey C. [Division of Pharmacology, Columbus, OH 43210 (United States); Mythreye, Karthikeyan [Duke University, Department of Medicine, Durham, NC 27708 (United States); Lee, Nam Y., E-mail: lee.5064@osu.edu [Division of Pharmacology, Columbus, OH 43210 (United States); Davis Heart and Lung Research Institute, Columbus, OH 43210 (United States)

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer Endoglin inhibits ERK activation in endothelial cells. Black-Right-Pointing-Pointer Endoglin is a regulator of c-Myc and cyclin D1 expression. Black-Right-Pointing-Pointer {beta}-arrestin2 interaction with endoglin is required for ERK/c-Myc repression. Black-Right-Pointing-Pointer Endoglin impedes cellular proliferation by targeting ERK-induced mitogenic signaling. -- Abstract: Endoglin is an endothelial-specific transforming growth factor beta (TGF-{beta}) co-receptor essential for angiogenesis and vascular remodeling. Endoglin regulates a wide range of cellular processes, including cell adhesion, migration, and proliferation, through TGF-{beta} signaling to canonical Smad and Smad-independent pathways. Despite its overall pro-angiogenic role in the vasculature, the underlying mechanism of endoglin action is poorly characterized. We previously identified {beta}-arrestin2 as a binding partner that causes endoglin internalization from the plasma membrane and inhibits ERK signaling towards endothelial migration. In the present study, we examined the mechanistic role of endoglin and {beta}-arrestin2 in endothelial cell proliferation. We show that endoglin impedes cell growth through sustained inhibition of ERK-induced c-Myc and cyclin D1 expression in a TGF-{beta}-independent manner. The down-regulation of c-Myc and cyclin D1, along with growth-inhibition, are reversed when the endoglin/{beta}-arrestin2 interaction is disrupted. Given that TGF-{beta}-induced Smad signaling potently represses c-Myc in most cell types, our findings here show a novel mechanism by which endoglin augments growth-inhibition by targeting ERK and key downstream mitogenic substrates.

  14. Establishment of c-myc-immortalized Kupffer cell line from a C57BL/6 mouse strain

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    Hiroshi Kitani

    2014-01-01

    Full Text Available We recently demonstrated in several mammalian species, a novel procedure to obtain liver-macrophages (Kupffer cells in sufficient numbers and purity using a mixed primary culture of hepatocytes. In this study, we applied this method to the C57BL/6 mouse liver and established an immortalized Kupffer cell line from this mouse strain. The hepatocytes from the C57BL/6 adult mouse liver were isolated by a two-step collagenase perfusion method and cultured in T25 culture flasks. Similar to our previous studies, the mouse hepatocytes progressively changed their morphology into a fibroblastic appearance after a few days of culture. After 7–10 days of culture, Kupffer-like cells, which were contaminants in the hepatocyte fraction at the start of the culture, actively proliferated on the mixed fibroblastic cell sheet. At this stage, a retroviral vector containing the human c-myc oncogene and neomycin resistance gene was introduced into the mixed culture. Gentle shaking of the culture flask, followed by the transfer and brief incubation of the culture supernatant, resulted in a quick and selective adhesion of Kupffer cells to a plastic dish surface. After selection with G418 and cloning by limiting dilutions, a clonal cell line (KUP5 was established. KUP5 cells displayed typical macrophage morphology and were stably passaged at 4–5 days intervals for more than 5 months, with a population doubling time of 19 h. KUP5 cells are immunocytochemically positive for mouse macrophage markers, such as Mac-1, F4/80. KUP5 cells exhibited substantial phagocytosis of polystyrene microbeads and the release of inflammatory cytokines upon lipopolysaccharide stimulation. Taken together, KUP5 cells provide a useful means to study the function of Kupffer cells in vitro.

  15. Mitochondrial structure, function and dynamics are temporally controlled by c-Myc.

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    J Anthony Graves

    Full Text Available Although the c-Myc (Myc oncoprotein controls mitochondrial biogenesis and multiple enzymes involved in oxidative phosphorylation (OXPHOS, the coordination of these events and the mechanistic underpinnings of their regulation remain largely unexplored. We show here that re-expression of Myc in myc-/- fibroblasts is accompanied by a gradual accumulation of mitochondrial biomass and by increases in membrane polarization and mitochondrial fusion. A correction of OXPHOS deficiency is also seen, although structural abnormalities in electron transport chain complexes (ETC are not entirely normalized. Conversely, the down-regulation of Myc leads to a gradual decrease in mitochondrial mass and a more rapid loss of fusion and membrane potential. Increases in the levels of proteins specifically involved in mitochondrial fission and fusion support the idea that Myc affects mitochondrial mass by influencing both of these processes, albeit favoring the latter. The ETC defects that persist following Myc restoration may represent metabolic adaptations, as mitochondrial function is re-directed away from producing ATP to providing a source of metabolic precursors demanded by the transformed cell.

  16. Induction of Pluripotency in Adult Equine Fibroblasts without c-MYC

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    Khodadad Khodadadi

    2012-01-01

    Full Text Available Despite tremendous efforts on isolation of pluripotent equine embryonic stem (ES cells, to date there are few reports about successful isolation of ESCs and no report of in vivo differentiation of this important companion species. We report the induction of pluripotency in adult equine fibroblasts via retroviral transduction with three transcription factors using OCT4, SOX2, and KLF4 in the absence of c-MYC. The cell lines were maintained beyond 27 passages (more than 11 months and characterized. The equine iPS (EiPS cells stained positive for alkaline phosphatase by histochemical staining and expressed OCT4, NANOG, SSEA1, and SSEA4. Gene expression analysis of the cells showed the expression of OCT4, SOX2 NANOG, and STAT3. The cell lines retained a euploid chromosome count of 64 after long-term culture cryopreservation. The EiPS demonstrated differentiation capacity for the three embryonic germ layers both in vitro by embryoid bodies (EBs formation and in vivo by teratoma formation. In conclusion, we report the derivation of iPS cells from equine adult fibroblasts and long-term maintenance using either of the three reprogramming factors.

  17. Profiling and bioinformatic analysis of circular RNA expression regulated by c-Myc.

    Science.gov (United States)

    Gou, Qiheng; Wu, Ke; Zhou, Jian-Kang; Xie, Yuxin; Liu, Lunxu; Peng, Yong

    2017-09-22

    The c-Myc transcription factor is involved in cell proliferation, cell cycle and apoptosis by activating or repressing transcription of multiple genes. Circular RNAs (circRNAs) are widely expressed non-coding RNAs participating in the regulation of gene expression. Using a high-throughput microarray assay, we showed that Myc regulates the expression of certain circRNAs. A total of 309 up- and 252 down-regulated circRNAs were identified. Among them, randomly selected 8 circRNAs were confirmed by real-time PCR. Subsequently, Myc-binding sites were found to generally exist in the promoter regions of differentially expressed circRNAs. Based on miRNA sponge mechanism, we constructed circRNAs/miRNAs network regulated by Myc, suggesting that circRNAs may widely regulate protein expression through miRNA sponge mechanism. Lastly, we took advantage of Gene Ontology and KEGG analyses to point out that Myc-regulated circRNAs could impact cell proliferation through affecting Ras signaling pathway and pathways in cancer. Our study for the first time demonstrated that Myc transcription factor regulates the expression of circRNAs, adding a novel component of the Myc tumorigenic program and opening a window to investigate the function of certain circRNAs in tumorigenesis.

  18. Direct labelling of the human P2X7 receptor and identification of positive and negative cooperativity of binding.

    Science.gov (United States)

    Michel, A D; Chambers, L J; Clay, W C; Condreay, J P; Walter, D S; Chessell, I P

    2007-05-01

    The P2X(7) receptor exhibits complex pharmacological properties. In this study, binding of a [(3)H]-labelled P2X(7) receptor antagonist to human P2X(7) receptors has been examined to further understand ligand interactions with this receptor. The P2X(7) receptor antagonist, N-[2-({2-[(2-hydroxyethyl)amino]ethyl}amino)-5-quinolinyl]-2-tricyclo[3.3.1.1(3,7)]dec-1-ylacetamide (compound-17), was radiolabelled with tritium and binding studies were performed using membranes prepared from U-2 OS or HEK293 cells expressing human recombinant P2X(7) receptors. Binding of [(3)H]-compound-17 was higher in membranes prepared from cells expressing P2X(7) receptors than from control cells and was inhibited by ATP suggesting labelled sites represented human P2X(7) receptors. Binding was reversible, saturable and modulated by P2X(7) receptor ligands (Brilliant Blue G, KN62, ATP, decavanadate). Furthermore, ATP potency was reduced in the presence of divalent cations or NaCl. Radioligand binding exhibited both positive and negative cooperativity. Positive cooperativity was evident from bell shaped Scatchard plots, reduction in radioligand dissociation rate by unlabelled compound-17 and enhancement of radioligand binding by KN62 and unlabelled compound-17. ATP and decavanadate inhibited binding in a negative cooperative manner as they enhanced radioligand dissociation. These data demonstrate that human P2X(7) receptors can be directly labelled and provide novel insights into receptor function. The positive cooperativity observed suggests that binding of compound-17 to one subunit in the P2X(7) receptor complex enhances subsequent binding to other P2X(7) subunits in the same complex. The negative cooperative effects of ATP suggest that ATP and compound-17 bind at separate, interacting, sites on the P2X(7) receptor.

  19. Combined use of nuclear phosphoprotein c-Myc and cellular phosphoprotein p53 for hepatocellular carcinoma detection in high-risk chronic hepatitis C patients.

    Science.gov (United States)

    Attallah, A M; El-Far, M; Abdelrazek, M A; Omran, M M; Attallah, A A; Elkhouly, A A; Elkenawy, H M; Farid, K

    2017-10-01

    Hepatocellular carcinoma (HCC) is a multistage process resulting from various genetic changes. We aimed to determine nuclear phosphoprotein c-Myc and cellular phosphoprotein p53 expression and to evaluate their importance in HCC diagnosis. One hundred and twenty chronic hepatitis C (CHC) patients (60 non-HCC CHC patients and 60 HCC patients who had a single small (c-Myc and p53 were identified in liver tissues and serum samples using immunostaining, western blot and ELISA. Immunohistochemical detection of c-Myc and p53 with monospecific antibodies revealed intense and diffuse cytoplasmic staining patterns. Accumulated mutant proteins, released from tumour cells into the extracellular serum, were detected at 62 KDa, for c-Myc, and 53 KDa, for p53, using western blotting. In contrast to alpha feto-protein, there was a significant increase (p c-Myc (86.7% vs. 6.7%) and p53 (78.3% vs. 8.3%) in the malignant vs. non-malignant patients. The parallel combination of c-Myc and p53 reach the absolute sensitivity (100%), for more accurate and reliable HCC detection (specificity was 87%). c-Myc and p53 are potential HCC diagnostic biomarkers, and convenient combinations of them could improve diagnostic accuracy of HCC.

  20. Protein kinase A antagonist inhibits β-catenin nuclear translocation, c-Myc and COX-2 expression and tumor promotion in ApcMin/+ mice

    Directory of Open Access Journals (Sweden)

    Brudvik Kristoffer W

    2011-12-01

    Full Text Available Abstract Background The adenomatous polyposis coli (APC protein is part of the destruction complex controlling proteosomal degradation of β-catenin and limiting its nuclear translocation, which is thought to play a gate-keeping role in colorectal cancer. The destruction complex is inhibited by Wnt-Frz and prostaglandin E2 (PGE2 - PI-3 kinase pathways. Recent reports show that PGE2-induced phosphorylation of β-catenin by protein kinase A (PKA increases nuclear translocation indicating two mechanisms of action of PGE2 on β-catenin homeostasis. Findings Treatment of ApcMin/+ mice that spontaneously develop intestinal adenomas with a PKA antagonist (Rp-8-Br-cAMPS selectively targeting only the latter pathway reduced tumor load, but not the number of adenomas. Immunohistochemical characterization of intestines from treated and control animals revealed that expression of β-catenin, β-catenin nuclear translocation and expression of the β-catenin target genes c-Myc and COX-2 were significantly down-regulated upon Rp-8-Br-cAMPS treatment. Parallel experiments in a human colon cancer cell line (HCT116 revealed that Rp-8-Br-cAMPS blocked PGE2-induced β-catenin phosphorylation and c-Myc upregulation. Conclusion Based on our findings we suggest that PGE2 act through PKA to promote β-catenin nuclear translocation and tumor development in ApcMin/+ mice in vivo, indicating that the direct regulatory effect of PKA on β-catenin nuclear translocation is operative in intestinal cancer.

  1. The long non-coding RNA GAS5 cooperates with the eukaryotic translation initiation factor 4E to regulate c-Myc translation.

    Directory of Open Access Journals (Sweden)

    Guangzhen Hu

    Full Text Available Long noncoding RNAs (lncRNAs are important regulators of transcription; however, their involvement in protein translation is not well known. Here we explored whether the lncRNA GAS5 is associated with translation initiation machinery and regulates translation. GAS5 was enriched with eukaryotic translation initiation factor-4E (eIF4E in an RNA-immunoprecipitation assay using lymphoma cell lines. We identified two RNA binding motifs within eIF4E protein and the deletion of each motif inhibited the binding of GAS5 with eIF4E. To confirm the role of GAS5 in translation regulation, GAS5 siRNA and in vitro transcribed GAS5 RNA were used to knock down or overexpress GAS5, respectively. GAS5 siRNA had no effect on global protein translation but did specifically increase c-Myc protein level without an effect on c-Myc mRNA. The mechanism of this increase in c-Myc protein was enhanced association of c-Myc mRNA with the polysome without any effect on protein stability. In contrast, overexpression of in vitro transcribed GAS5 RNA suppressed c-Myc protein without affecting c-Myc mRNA. Interestingly, GAS5 was found to be bound with c-Myc mRNA, suggesting that GAS5 regulates c-Myc translation through lncRNA-mRNA interaction. Our findings have uncovered a role of GAS5 lncRNA in translation regulation through its interactions with eIF4E and c-Myc mRNA.

  2. Melatonin disturbs SUMOylation mediated crosstalk between c-Myc and Nestin via MT1 activation and promotes the sensitivity of Paclitaxel in brain cancer stem cells.

    Science.gov (United States)

    Lee, Hyemin; Lee, Hyo-Jung; Jung, Ji Hoon; Shin, Eun Ah; Kim, Sung-Hoon

    2018-04-14

    Here the underlying antitumor mechanism of melatonin and its potency as a sensitizer of Paclitaxel was investigated in X02 cancer stem cells. Melatonin suppressed sphere formation and induced G2/M arrest in X02 cells expressing Nestin, CD133, CXCR4 and SOX-2 as biomarkers of stemness. Furthermore, melatonin reduced the expression of CDK2, CDK4, cyclin D1, cyclin E, and c-Myc and upregulated cyclin B1 in X02 cells. Notably, genes of c-Myc related mRNAs were differentially expressed in melatonin treated X02 cells by microarray analysis. Consistently, melatonin reduced the expression of c-Myc at mRNA and protein levels, which was blocked by MG132. Of note, overexpression of c-Myc increased the expression of Nestin, while overexpression of Nestin enhanced c-Myc through crosstalk despite different locations, nucleus and cytoplasm. Interestingly, melatonin attenuated small ubiquitin-related modifier-1 (SUMO-1) more than SUMO-2 or SUMO-3 and disturbed nuclear translocation of Nestin for direct binding to c-Myc by SUMOylation of SUMO-1 protein by immunofluorescence and immunoprecipitation. Also, melatonin reduced trimethylated histone H3K4me3 and H3K36me3 more than dimethylation in X02 cells by Western blotting and Chromatin immunoprecipitation assay. Notably, melatonin upregulated MT1, not MT2, in X02 cells and melatonin receptor inhibitor Luzindole blocked the ability of melatonin to decrease the expression of Nestin, p-c-Myc(S62) and c-Myc. Furthermore, melatonin promoted cytotoxicity, sub G1 accumulation and apoptotic body formation by Paclitaxcel in X02 cells. Taken together, these findings suggest that melatonin inhibits stemness via suppression of c-Myc, Nestin, and histone methylation via MT1 activation and promotes anticancer effect of Paclitaxcel in brain cancer stem cells. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. Focal Adhesion Kinase Is Required for Intestinal Regeneration and Tumorigenesis Downstream of Wnt/c-Myc Signaling

    Science.gov (United States)

    Ashton, Gabrielle H.; Morton, Jennifer P.; Myant, Kevin; Phesse, Toby J.; Ridgway, Rachel A.; Marsh, Victoria; Wilkins, Julie A.; Athineos, Dimitris; Muncan, Vanesa; Kemp, Richard; Neufeld, Kristi; Clevers, Hans; Brunton, Valerie; Winton, Douglas J.; Wang, Xiaoyan; Sears, Rosalie C.; Clarke, Alan R.; Frame, Margaret C.; Sansom, Owen J.

    2012-01-01

    SUMMARY The intestinal epithelium has a remarkable capacity to regenerate after injury and DNA damage. Here, we show that the integrin effector protein Focal Adhesion Kinase (FAK) is dispensable for normal intestinal homeostasis and DNA damage signaling, but is essential for intestinal regeneration following DNA damage. Given Wnt/c-Myc signaling is activated following intestinal regeneration, we investigated the functional importance of FAK following deletion of the Apc tumor suppressor protein within the intestinal epithelium. Following Apc loss, FAK expression increased in a c-Myc-dependent manner. Codeletion of Apc and Fak strongly reduced proliferation normally induced following Apc loss, and this was associated with reduced levels of phospho-Akt and suppression of intestinal tumorigenesis in Apc heterozygous mice. Thus, FAK is required downstream of Wnt Signaling, for Akt/mTOR activation, intestinal regeneration, and tumorigenesis. Importantly, this work suggests that FAK inhibitors may suppress tumorigenesis in patients at high risk of developing colorectal cancer. PMID:20708588

  4. Identification of endogenous surrogate ligands for human P2Y12 receptors by in silico and in vitro methods

    International Nuclear Information System (INIS)

    Nonaka, Yosuke; Hiramoto, Takeshi; Fujita, Norihisa

    2005-01-01

    Endogenous ligands acting on a human P2Y 12 receptor, one of the G-protein coupled receptors, were searched by in silico screening against our own database, which contains more than 500 animal metabolites. The in silico screening using the docking software AutoDock resulted in selection of cysteinylleukotrienes (CysLTs) and 5-phosphoribosyl 1-pyrophosphate (PRPP), with high free energy changes, in addition to the known P2Y 12 ligands such as 2MeSADP and ADP. These candidates were subjected to an in vitro Ca 2+ assay using the CHO cells stably expressing P2Y 12 -G 16 α fusion proteins. We found that CysLTE4 and PRPP acted on the P2Y 12 receptor as agonists with the EC 50 values of 1.3 and 7.8 nM, respectively. Furthermore, we analyzed the phylogenetic relationship of the P2Y, P2Y-like, and CysLT receptors based on sequence alignment followed by evolutionary analyses. The analyses showed that the P2Y 12 , P2Y 13 , P2Y 14 , GPR87, CysLT-1, and CysLT-2 receptors formed a P2Y-related receptor subfamily with common sequence motifs in the transmembrane regions

  5. Using a Novel Transgenic Mouse Model to Study c-Myc Oncogenic Pathway in Castration Resistance and Chemoresistance of Prostate Cancer

    Science.gov (United States)

    2017-12-01

    AWARD NUMBER: W81XWH-13-1-0162 TITLE: Using a Novel Transgenic Mouse Model to Study c -Myc Oncogenic Pathway in Castration Resistance and...DATES COVERED 15Sept2013 - 14Sept2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Using a Novel Transgenic Mouse Model to Study c -Myc Oncogenic...ABSTRACT We previously made a PB-Cre4/Ai-Myc model for Cre-induced and androgen-independent expression of c -Myc and Luc2 in prostate. This is designed

  6. Shikonin regulates C-MYC and GLUT1 expression through the MST1-YAP1-TEAD1 axis

    Czech Academy of Sciences Publication Activity Database

    Vališ, Karel; Talacko, Pavel; Grobárová, Valeria; Černý, J.; Novák, Petr

    2016-01-01

    Roč. 349, č. 2 (2016), s. 273-281 ISSN 0014-4827 R&D Projects: GA ČR(CZ) GP14-21095P; GA ČR GA13-16565S; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61388971 Keywords : Hippo * Glycolysis * C-MYC Subject RIV: EE - Microbiology, Virology Impact factor: 3.546, year: 2016

  7. Conserved features of cancer cells define their sensitivity to HAMLET-induced death; c-Myc and glycolysis.

    Science.gov (United States)

    Storm, P; Aits, S; Puthia, M K; Urbano, A; Northen, T; Powers, S; Bowen, B; Chao, Y; Reindl, W; Lee, D Y; Sullivan, N L; Zhang, J; Trulsson, M; Yang, H; Watson, J D; Svanborg, C

    2011-12-01

    HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here, we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small-hairpin RNA (shRNA) inhibition, proteomic and metabolomic technology, we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, HAMLET sensitivity was modified by the glycolytic state of tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen, hexokinase 1 (HK1), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 and hypoxia-inducible factor 1α modified HAMLET sensitivity. HK1 was shown to bind HAMLET in a protein array containing ∼8000 targets, and HK activity decreased within 15 min of HAMLET treatment, before morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 min. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene addiction or the Warburg effect.

  8. Conserved features of cancer cells define their sensitivity of HAMLET-induced death; c-Myc and glycolysis

    Science.gov (United States)

    Storm, Petter; Puthia, Manoj Kumar; Aits, Sonja; Urbano, Alexander; Northen, Trent; Powers, Scott; Bowen, Ben; Chao, Yinxia; Reindl, Wolfgang; Lee, Do Yup; Sullivan, Nancy Liu; Zhang, Jianping; Trulsson, Maria; Yang, Henry; Watson, James; Svanborg, Catharina

    2014-01-01

    HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small hairpin RNA inhibition, proteomic and metabolomic technology we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted the sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, the HAMLET sensitivity was modified by the glycolytic state of the tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen Hexokinase 1, PFKFB1 and HIF1α modified HAMLET sensitivity. Hexokinase 1 was shown to bind HAMLET in a protein array containing approximately 8000 targets and Hexokinase activity decreased within 15 minutes of HAMLET treatment, prior to morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. The glycolytic machinery was modified and glycolysis was shifted towards the pentose phosphate pathway. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 minutes. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene-addiction or the Warburg effect. PMID:21643007

  9. MYCT1-TV, A Novel MYCT1 Transcript, Is Regulated by c-Myc and May Participate in Laryngeal Carcinogenesis

    Science.gov (United States)

    Fu, Shuang; Guo, Yan; Chen, Hong; Xu, Zhen-Ming; Qiu, Guang-Bin; Zhong, Ming; Sun, Kai-Lai; Fu, Wei-Neng

    2011-01-01

    Background MYCT1, a putative target of c-Myc, is a novel candidate tumor suppressor gene cloned from laryngeal squamous cell carcinoma (LSCC). Its transcriptional regulation and biological effects on LSCC have not been clarified. Methodology/Principal Findings Using RACE assay, we cloned a 1106 bp transcript named Myc target 1 transcript variant 1 (MYCT1-TV) and confirmed its transcriptional start site was located at 140 bp upstream of the ATG start codon of MYCT1-TV. Luciferase, electrophoretic mobility shift and chromatin immunoprecipitation assays confirmed c-Myc could regulate the promoter activity of MYCT1-TV by specifically binding to the E-box elements within −886 to −655 bp region. These results were further verified by site-directed mutagenesis and RNA interference (RNAi) assays. MYCT1-TV and MYCT1 expressed lower in LSCC than those in paired adjacent normal laryngeal tissues, and overexpression of MYCT1-TV and MYCT1 could inhibit cell proliferation and invasion and promote apoptosis in LSCC cells. Conclusions/Significance Our data indicate that MYCT1-TV, a novel MYCT1 transcript, is regulated by c-Myc and down-regulation of MYCT1-TV/MYCT1 could contribute to LSCC development and function. PMID:21998677

  10. Apoptosis and cell proliferation in the development of gastric carcinomas: associations with c-myc and p53 protein expression.

    Science.gov (United States)

    Ishii, Hideaki H; Gobé, Glenda C; Pan, Wenshen; Yoneyama, Juichi; Ebihara, Yoshiro

    2002-09-01

    Patients with gastric carcinomas have a poor prognosis and low survival rates. The aim of the present paper was to characterize cellular and molecular properties to provide insight into aspects of tumor progression in early compared with advanced gastric cancers. One hundred and nine graded gastric carcinomas (early or advanced stage, undifferentiated or differentiated type) with paired non-cancer tissue were studied to define the correlation between apoptosis (morphology, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling), cell proliferation (Ki-67 expression, morphology) and expression and localization of two proteins frequently having altered expression in cancers, namely p53 and c-myc. Overall, apoptosis was lower in early stage, differentiated and undifferentiated gastric carcinomas compared with advanced-stage cancers. Cell proliferation was comparatively high in all stages. There was a high level of p53 positivity in all stages. Only the early- and advanced-stage undifferentiated cancers that were p53 positive had a significantly higher level of apoptosis (P cancers that had either c-myc or p53-positivity. The results indicate that low apoptosis and high cell proliferation combine to drive gastric cancer development. The molecular controls for high cell proliferation of the early stage undifferentiated gastric cancers involve overexpression of both p53 and c-myc. Overexpression of p53 may also control cancer development in that its expression is associated with higher levels of apoptosis in early and late-stage undifferentiated, cancers. Copyright 2002 Blackwell Publishing Asia Pty Ltd

  11. Immunodetection of rasP21 and c-myc oncogenes in oral mucosal swab preparation from clove cigarette smokers

    Directory of Open Access Journals (Sweden)

    Silvi Kintawati

    2008-12-01

    Full Text Available Background: Smoking is the biggest factor for oral cavity malignancy. Some carcinogens found in cigar will stimulate epithel cell in oral cavity and cause mechanism disturbance on tissue resistance and produce abnormal genes (oncogenes. Oncogenes ras and myc are found on malignant tumor in oral cavity which are associated with smoking. Purpose: This research is to find the expression of oncogenes rasP21 and c-myc in oral mucosa epithelial of smoker with immunocytochemistry reaction. Methods: An oral mucosal swab was performed to 30 smokers categorized as light, moderate, and chain, and 10 non smokers which was followed by immunocytochemistry reaction using antibody towards oncogene rasP21 and c-myc is reacted to identify the influence of smoking towards malignant tumor in oral cavity. The result is statistically analyzed using Kruskal-Wallis test. Result: Based on the observation result of oncogene rasP21reaction, it shows that there is significant difference between non smoker group and light smoker, compared to moderate and chain smoker group (p < 0.01. On the other side, the observation result of oncogene c-myc indicates that there is no significant difference between the group of non smokers and the group of light, moderate, and chain smokers (p > 0.05. Conclusion: The higher the possibility of oral cavity malignancy and that the antibody for rasP21 oncogene can be used as a marker for early detection of oral cavity malignancy caused by smoking.

  12. c-Myc Represses Transcription of Epstein-Barr Virus Latent Membrane Protein 1 Early after Primary B Cell Infection.

    Science.gov (United States)

    Price, Alexander M; Messinger, Joshua E; Luftig, Micah A

    2018-01-15

    Recent evidence has shown that the Epstein-Barr virus (EBV) oncogene LMP1 is not expressed at high levels early after EBV infection of primary B cells, despite its being essential for the long-term outgrowth of immortalized lymphoblastoid cell lines (LCLs). In this study, we found that expression of LMP1 increased 50-fold between 7 days postinfection and the LCL state. Metabolic labeling of nascent transcribed mRNA indicated that this was primarily a transcription-mediated event. EBNA2, the key viral transcription factor regulating LMP1, and CTCF, an important chromatin insulator, were recruited to the LMP1 locus similarly early and late after infection. However, the activating histone H3K9Ac mark was enriched at the LMP1 promoter in LCLs relative to that in infected B cells early after infection. We found that high c-Myc activity in EBV-infected lymphoma cells as well as overexpression of c-Myc in an LCL model system repressed LMP1 transcription. Finally, we found that chemical inhibition of c-Myc both in LCLs and early after primary B cell infection increased LMP1 expression. These data support a model in which high levels of endogenous c-Myc activity induced early after primary B cell infection directly repress LMP1 transcription. IMPORTANCE EBV is a highly successful pathogen that latently infects more than 90% of adults worldwide and is also causally associated with a number of B cell malignancies. During the latent life cycle, EBV expresses a set of viral oncoproteins and noncoding RNAs with the potential to promote cancer. Critical among these is the viral latent membrane protein LMP1. Prior work suggests that LMP1 is essential for EBV to immortalize B cells, but our recent work indicates that LMP1 is not produced at high levels during the first few weeks after infection. Here we show that transcription of the LMP1 gene can be negatively regulated by a host transcription factor, c-Myc. Ultimately, understanding the regulation of EBV oncogenes will allow us

  13. Use of a transfected and amplified Drosophila heat shock promoter construction for inducible production of toxic mouse c-myc proteins in CHO cells

    International Nuclear Information System (INIS)

    Wurm, F.M.; Gwinn, K.A.; Papoulas, O.; Pallavicini, M.; Kingston, R.E.

    1987-01-01

    After transfection and selection with methotrexate, CHO cell lines were established which contained up to 2000 copies of an expression vector for c-myc protein. The vector contained the Drosophila heat shock protein 70 (hsp70) promoter fused with the coding region of the mouse c-myc gene. Incubation of cells for up to 3 hours at 43 0 C resulted in at least a 100-fold induction of recombinant c-myc mRNA. When cells were shifted back to 37 0 C, within 1 to 4 hours, this RNA was translated into protein to yield about 250 μg per 10 9 cells. Cells died a few hours later, suggesting that high concentrations of intracellular c-myc are cytotoxic. 47 refs., 5 figs

  14. Atomic resolution view into the structure–function relationships of the human myelin peripheral membrane protein P2

    Energy Technology Data Exchange (ETDEWEB)

    Ruskamo, Salla [University of Oulu, Oulu (Finland); University of Oulu, Oulu (Finland); Yadav, Ravi P. [Banaras Hindu University, Varanasi (India); Helmholtz Centre for Infection Research (CSSB-HZI), German Electron Synchrotron (DESY), Hamburg (Germany); Sharma, Satyan; Lehtimäki, Mari [University of Oulu, Oulu (Finland); University of Oulu, Oulu (Finland); Laulumaa, Saara [University of Oulu, Oulu (Finland); University of Oulu, Oulu (Finland); Helmholtz Centre for Infection Research (CSSB-HZI), German Electron Synchrotron (DESY), Hamburg (Germany); Aggarwal, Shweta; Simons, Mikael [Max Planck Institute for Experimental Medicine, Göttingen (Germany); Bürck, Jochen; Ulrich, Anne S. [Karlsruhe Institute for Technology (KIT), Karlsruhe (Germany); Juffer, André H. [University of Oulu, Oulu (Finland); University of Oulu, Oulu (Finland); Kursula, Inari [University of Oulu, Oulu (Finland); Helmholtz Centre for Infection Research (CSSB-HZI), German Electron Synchrotron (DESY), Hamburg (Germany); Kursula, Petri, E-mail: petri.kursula@oulu.fi [University of Oulu, Oulu (Finland); University of Oulu, Oulu (Finland); Helmholtz Centre for Infection Research (CSSB-HZI), German Electron Synchrotron (DESY), Hamburg (Germany); University of Hamburg, Hamburg (Germany)

    2014-01-01

    The structure of the human myelin peripheral membrane protein P2 has been refined at 0.93 Å resolution. In combination with functional experiments in vitro, in vivo and in silico, the fine details of the structure–function relationships in P2 are emerging. P2 is a fatty acid-binding protein expressed in vertebrate peripheral nerve myelin, where it may function in bilayer stacking and lipid transport. P2 binds to phospholipid membranes through its positively charged surface and a hydrophobic tip, and accommodates fatty acids inside its barrel structure. The structure of human P2 refined at the ultrahigh resolution of 0.93 Å allows detailed structural analyses, including the full organization of an internal hydrogen-bonding network. The orientation of the bound fatty-acid carboxyl group is linked to the protonation states of two coordinating arginine residues. An anion-binding site in the portal region is suggested to be relevant for membrane interactions and conformational changes. When bound to membrane multilayers, P2 has a preferred orientation and is stabilized, and the repeat distance indicates a single layer of P2 between membranes. Simulations show the formation of a double bilayer in the presence of P2, and in cultured cells wild-type P2 induces membrane-domain formation. Here, the most accurate structural and functional view to date on P2, a major component of peripheral nerve myelin, is presented, showing how it can interact with two membranes simultaneously while going through conformational changes at its portal region enabling ligand transfer.

  15. Identification of Human P2X1 Receptor-interacting Proteins Reveals a Role of the Cytoskeleton in Receptor Regulation*

    Science.gov (United States)

    Lalo, Ulyana; Roberts, Jonathan A.; Evans, Richard J.

    2011-01-01

    P2X1 receptors are ATP-gated ion channels expressed by smooth muscle and blood cells. Carboxyl-terminally His-FLAG-tagged human P2X1 receptors were stably expressed in HEK293 cells and co-purified with cytoskeletal proteins including actin. Disruption of the actin cytoskeleton with cytochalasin D inhibited P2X1 receptor currents with no effect on the time course of the response or surface expression of the receptor. Stabilization of the cytoskeleton with jasplakinolide had no effect on P2X1 receptor currents but decreased receptor mobility. P2X2 receptor currents were unaffected by cytochalasin, and P2X1/2 receptor chimeras were used to identify the molecular basis of actin sensitivity. These studies showed that the intracellular amino terminus accounts for the inhibitory effects of cytoskeletal disruption similar to that shown for lipid raft/cholesterol sensitivity. Stabilization of the cytoskeleton with jasplakinolide abolished the inhibitory effects of cholesterol depletion on P2X1 receptor currents, suggesting that lipid rafts may regulate the receptor through stabilization of the cytoskeleton. These studies show that the cytoskeleton plays an important role in P2X1 receptor regulation. PMID:21757694

  16. Lack of induction of tissue transglutaminase but activation of the preexisting enzyme in c-Myc-induced apoptosis of CHO cells.

    Science.gov (United States)

    Balajthy, Z; Kedei, N; Nagy, L; Davies, P J; Fésüs, L

    1997-07-18

    The intracellular activity and expression of tissue transglutaminase, which crosslinks proteins through epsilon(gamma-glutamyl)lysine isodipeptide bond, was investigated in CHO cells and those stably transfected with either inducible c-Myc (which leads to apoptosis) or with c-myc and the apoptosis inhibitor Bcl-2. Protein-bound cross-link content was significantly higher when apoptosis was induced by c-Myc while the concomitant presence of Bcl-2 markedly reduced both apoptosis and enzymatic protein cross-linking. The expression of tissue transglutaminase did not change following the initiation of apoptosis by c-Myc or when it was blocked by Bcl-2. Studying transiently co-transfected elements of the mouse tissue transglutaminase promoter linked to a reporter enzyme revealed their overall repression in cells expressing c-Myc. This repression was partially suspended in cells also carrying Bcl-2. Our data suggest that tissue transglutaminase is not induced when c-Myc initiates apoptosis but the pre-existing endogenous enzyme is activated.

  17. Pre-clinical analysis of changes in intra-cellular biochemistry of glioblastoma multiforme (GBM) cells due to c-Myc silencing.

    Science.gov (United States)

    Rajagopalan, Vishal; Vaidyanathan, Muthukumar; Janardhanam, Vanisree Arambakkam; Bradner, James E

    2014-10-01

    Glioblastoma Multiforme (GBM) is an aggressive form of brain Tumor that has few cures. In this study, we analyze the anti-proliferative effects of a new molecule JQ1 against GBMs induced in Wistar Rats. JQ1 is essentially a Myc inhibitor. c-Myc is also known for altering the biochemistry of a tumor cell. Therefore, the study is intended to analyze certain other oncogenes associated with c-Myc and also the change in cellular biochemistry upon c-Myc inhibition. The quantitative analysis of gene expression gave a co-expressive pattern for all the three genes involved namely; c-Myc, Bcl-2, and Akt. The cellular biochemistry analysis by transmission electron microscopy revealed high glycogen and lipid aggregation in Myc inhibited cells and excessive autophagy. The study demonstrates the role of c-Myc as a central metabolic regulator and Bcl-2 and Akt assisting in extending c-Myc half-life as well as in regulation of autophagy, so as to regulate cell survival on the whole. The study also demonstrates that transient treatment by JQ1 leads to aggressive development of tumor and therefore, accelerating death, emphasizing the importance of dosage fixation, and duration for clinical use in future.

  18. Understanding Endogenous c-Myc Function in Human Breast Cancer Development

    National Research Council Canada - National Science Library

    Xia, Bing

    2003-01-01

    My research is focused on BRCA2, whose mutation has been implicated in the development of breast, ovarian, prostate, pancreatic cancers and Fanconi anemia BRCA2 is an extremely large protein that is challenging% to study...

  19. Regulation of c-Myc mRNA by L11 in Response to UV and Gamma Irradiation

    Science.gov (United States)

    2014-12-01

    the nucleolus fol- lowed by their transport into the cytoplasm (50). This process requires coordinated transcription catalyzed by all three RNA...these RPs, including L11, are released from the nucleolus or from intact ribosomes to suppress MDM2 (68). However, whether L11 suppresses c-Myc in...centrifugation. For isolation of the nucleolus fraction, the nuclear pellets were resuspended in buffer S1 containing 0.25 M sucrose and 10 mM MgCl2, layered over

  20. 1,25 dihydroxyvitamin D3 (1,25) regulation of c-myc mRNA in HL-60 leukemia cells

    International Nuclear Information System (INIS)

    Simpson, R.U.; Bresnick, E.H.; Begley, D.A.

    1986-01-01

    Recently, 1,25 was shown to induce differentiation and decrease c-myc levels in HL-60 cells. The authors have confirmed these observations by RNA dot blot analysis. Cells treated with 50 nM 1,25 for 4, 24 and 48 hr showed c-myc mRNA levels of 26, 17 and 15% of control respectively. β-Actin mRNA levels were not altered. To ascertain whether 1, 25 regulated c-myc transcriptionally, an HL-60 nuclear RNA runoff assay was developed. Assay of total nuclei transcriptional activity revealed that 50% of RNA elongation was α-amanitin (0.8 μg/ml) sensitive and was linear with nuclei concentration (0.1-1 x 10 7 nuclei). 1,25 (50 nM) treated (45-96 hr) cells had decreased (approx.40%) total transcription rate relative to control. Decreased total RNA synthesis occurred concomitant with NBT reducing activity. 32 P-RNA runoff transcripts from HL-60 nuclei were hybridized to excess (5 μg DNA was excess) Pst I linearized c-myc and β-actin clones (in pBR322) immobilized on nitrocellulose filter. 32 P-RNA input from 2 x 10 6 to 2 x 10 7 cpm yielded linear hybridization signal. Analysis of blot dot intensity revealed no difference in transcription of c-myc in nuclei from 1,25 dosed or control cells. (myc/actin ratios: 1,25 (50 nM, 72 hr) =1.1 +/- 0.3 and control (72 hr) = 1.0, N=3 or 2 or 3 dots ea). These preliminary data suggest 1,25 does not affect c-myc transcription in HL-60 nuclei and may regulate c-myc mRNA post-transcriptionally

  1. The scavenger activity of the human P2X7 receptor differs from P2X7 pore function by insensitivity to antagonists, genetic variation and sodium concentration: Relevance to inflammatory brain diseases.

    Science.gov (United States)

    Ou, Amber; Gu, Ben J; Wiley, James S

    2018-04-01

    Activation of P2X7 receptors is widely recognised to initiate proinflammatory responses. However P2X7 also has a dual function as a scavenger receptor which is active in the absence of ATP and plasma proteins and may be important in central nervous system (CNS) diseases. Here, we investigated both P2X7 pore formation and its phagocytic function in fresh human monocytes (as a model of microglia) by measuring ATP-induced ethidium dye uptake and fluorescent bead uptake respectively. This was studied in monocytes expressing various polymorphic variants as well as in the presence of different P2X7 antagonists and ionic media. P2X7-mediated phagocytosis was found to account for about half of Latrunculin (or Cytochalasin D)-sensitive bead engulfment by fresh human monocytes. Monocytes harbouring P2X7 Ala348Thr or Glu496Ala polymorphic variants showed increase or loss of ethidium uptake respectively, but these changes in pore formation did not always correspond to the changes in phagocytosis of YG beads. Unlike pore function, P2X7-mediated phagocytosis was not affected by three potent selective P2X7 antagonists and remained identical in Na + and K + media. Taken together, our results show that P2X7 is a scavenger receptor with important function in the CNS but its phagocytic function has features distinct from its pore function. Both P2X7 pore formation and P2X7-mediated phagocytosis should be considered in the design of new P2X7 antagonists for the treatment of CNS diseases. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinmn-iridium stents in rabbits and its effect on apoptosis

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 许香广; 胡雪松; 方卫华; 邝碧娟

    2004-01-01

    Background Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells(VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs. Methods Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 μg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c- myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n=16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n=16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n=4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM). Results According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the

  3. Involvement of SIRT1 in hypoxic down-regulation of c-Myc and β-catenin and hypoxic preconditioning effect of polyphenols

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kyung-Soo [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Park, Jun-Ik [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Kim, Mi-Ju; Kim, Hak-Bong; Lee, Jae-Won [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Dao, Trong Tuan; Oh, Won Keun [BK21 Project Team, College of Pharmacy, Chosun University, Gwangju (Korea, Republic of); Kang, Chi-Dug, E-mail: kcdshbw@pusan.ac.kr [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Kim, Sun-Hee, E-mail: ksh7738@pusan.ac.kr [Department of Biochemistry, Pusan National University School of Medicine, Yangsan (Korea, Republic of); Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan (Korea, Republic of)

    2012-03-01

    SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and β-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1α and down-regulation of c-Myc and β-catenin expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1α expression but increased c-Myc and β-catenin expression. SIRT1 was also found to stabilize HIF-1α protein and destabilize c-Myc, β-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1α and down-regulated c-Myc, PHD2 and β-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1α and SIRT1 and down-regulating c-Myc, PHD2, and β-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1α, SIRT1, c-Myc, β-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ► SIRT1 expression is increased in hypoxia

  4. NM23-H2 may play an indirect role in transcriptional activation of c-myc gene expression but does not cleave the nuclease hypersensitive element III1

    International Nuclear Information System (INIS)

    Dexheimer, Thomas S.; Carey, Steven S.; Zuohe, Song; Gokhale, Vijay M.; Hu, Xiaohui; Murata, Lauren B.; Maes, Estelle M.; Weichsel, Andrzej; Sun, Daekyu; Meuillet, Emmanuelle J.; Montfort, William R.; Hurley, Laurence H.

    2009-01-01

    The formation of G-quadruplex structures within the nuclease hypersensitive element (NHE) III 1 region of the c-myc promoter and the ability of these structures to repress c-myc transcription have been well established. However, just how these extremely stable DNA secondary structures are transformed to activate c-myc transcription is still unknown. NM23-H2/nucleoside diphosphate kinase B has been recognized as an activator of c-myc transcription via interactions with the NHE III 1 region of the c-myc gene promoter. Through the use of RNA interference, we confirmed the transcriptional regulatory role of NM23-H2. In addition, we find that further purification of NM23-H2 results in loss of the previously identified DNA strand cleavage activity, but retention of its DNA binding activity. NM23-H2 binds to both single-stranded guanine- and cytosine-rich strands of the c-myc NHE III 1 and, to a lesser extent, to a random single-stranded DNA template. However, it does not bind to or cleave the NHE III 1 in duplex form. Significantly, potassium ions and compounds that stabilize the G-quadruplex and i-motif structures have an inhibitory effect on NM23-H2 DNA-binding activity. Mutation of Arg 88 to Ala 88 (R88A) reduced both DNA and nucleotide binding but had minimal effect on the NM23-H2 crystal structure. On the basis of these data and molecular modeling studies, we have proposed a stepwise trapping-out of the NHE III 1 region in a single-stranded form, thus allowing single-stranded transcription factors to bind and activate c-myc transcription. Furthermore, this model provides a rationale for how the stabilization of the G-quadruplex or i-motif structures formed within the c-myc gene promoter region can inhibit NM23-H2 from activating c-myc gene expression.

  5. Involvement of SIRT1 in hypoxic down-regulation of c-Myc and β-catenin and hypoxic preconditioning effect of polyphenols

    International Nuclear Information System (INIS)

    Hong, Kyung-Soo; Park, Jun-Ik; Kim, Mi-Ju; Kim, Hak-Bong; Lee, Jae-Won; Dao, Trong Tuan; Oh, Won Keun; Kang, Chi-Dug; Kim, Sun-Hee

    2012-01-01

    SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and β-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1α and down-regulation of c-Myc and β-catenin expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1α expression but increased c-Myc and β-catenin expression. SIRT1 was also found to stabilize HIF-1α protein and destabilize c-Myc, β-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1α and down-regulated c-Myc, PHD2 and β-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1α and SIRT1 and down-regulating c-Myc, PHD2, and β-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1α, SIRT1, c-Myc, β-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ► SIRT1 expression is increased in hypoxia

  6. Identification of a c-Jun N-terminal kinase-2-dependent signal amplification cascade that regulates c-Myc levels in ras transformation

    DEFF Research Database (Denmark)

    Mathiasen, D.P.; Egebjerg, C.; Andersen, S.H.

    2012-01-01

    are essential for ras transformation. Previous studies show that ERK-mediated serine 62 phosphorylation protects c-Myc from proteasomal degradation. ERK is, however, not alone sufficient to stabilize c-Myc but requires the cooperation of cancerous inhibitor of protein phosphatase 2A (CIP2A), an oncogene...... that counteracts protein phosphatase 2A-mediated dephosphorylation of c-Myc. Here we show that JNK2 regulates Cip2a transcription via ATF2. ATF2 and c-Myc cooperate to activate the transcription of ATF3. Remarkably, not only ectopic JNK2, but also ectopic ATF2, CIP2A, c-Myc and ATF3 are sufficient to rescue...... the defective ras transformation of JNK2-deficient cells. Thus, these data identify the key signal converging point of JNK2 and ERK pathways and underline the central role of CIP2A in ras transformation.Oncogene advance online publication, 27 June 2011; doi:10.1038/onc.2011.230....

  7. P2X1 receptors localized in lipid rafts mediate ATP motor responses in the human vas deferens longitudinal muscles.

    Science.gov (United States)

    Donoso, María Verónica; Norambuena, Andrés; Navarrete, Camilo; Poblete, Inés; Velasco, Alfredo; Huidobro-Toro, Juan Pablo

    2014-02-01

    To assess the role of the P2X1 receptors (P2X1R) in the longitudinal and circular layers of the human vas deferens, ex vivo-isolated strips or rings were prepared from tissue biopsies to record isometric contractions. To ascertain its membrane distribution, tissue extracts were analyzed by immunoblotting following sucrose gradient ultracentrifugation. ATP, alpha,beta-methylene ATP, or electrical field stimulation elicited robust contractions of the longitudinal layer but not of the circular layer which demonstrated inconsistent responses. Alpha,beta-methylene ATP generated stronger and more robust contractions than ATP. In parallel, prostatic segments of the rat vas deferens were examined. The motor responses in both species were not sustained but decayed within the first minute, showing desensitization to additional applications. Cross-desensitization was established between alpha,beta-methylene ATP or ATP-evoked contractions and electrical field stimulation-induced contractions. Full recovery of the desensitized motor responses required more than 30 min and showed a similar pattern in human and rat tissues. Immunoblot analysis of the human vas deferens extracts revealed a P2X1R oligomer of approximately 200 kDa under nonreducing conditions, whereas dithiothreitol-treated extracts showed a single band of approximately 70 kDa. The P2X1R was identified in ultracentrifugation fractions containing 15%-29% sucrose; the receptor localized in the same fractions as flotillin-1, indicating that it regionalized into smooth muscle lipid rafts. In conclusion, ATP plays a key role in human vas deferens contractile responses of the longitudinal smooth muscle layer, an effect mediated through P2X1Rs.

  8. Controlled and localized delivery of c-myc AS-ODN to cells by 3-aminopropyl-trimethoxylsilane modified SBA-15 mesoporous silica

    Science.gov (United States)

    Zhang, Juan; Chen, Minmin; Zhao, Xiqiu; Zhang, Min; Mao, Jinxiang; Cao, Xichuan; Zhang, Zhuoqi

    2018-01-01

    SBA-15 mesoporous silicate was synthesized and functionalized with 3-aminopropyl organic groups through a post-synthesis method. The materials were characterized consecutively by powder X-ray diffraction (XRD), N2 adsorption/desorption analysis and solid-state magic-angle spinning 29Si nuclear magnetic resonance (MAS NMR). Human c-myc anti-sense oligodeoxyneucleotide (AS-ODN) was selected as a model molecule to be loaded onto the surface of bare and functionalized SBA-15 via different loading conditions. It has been found that the amount of AS-ODN incorporated into the porous matrix is strongly dependent on the surface properties, pH of the loading solvent and AS-ODN concentration. The release behaviour of AS-ODN from modified SBA-15 materials was also investigated and depended on conditions chosen. Cellular uptake of the eluted AS-ODN into Hela cells was observed by fluorescent microscopy. The materials showed excellent cytocompatibility. The AS-ODN keeps full transfection and expression activities indicating its structural integrity. The functionalized SBA-15 is an excellent prospect as a biomedical material candidate for the future.

  9. Loss of connective tissue growth factor as an unfavorable prognosis factor activates miR-18b by PI3K/AKT/C-Jun and C-Myc and promotes cell growth in nasopharyngeal carcinoma.

    Science.gov (United States)

    Yu, X; Zhen, Y; Yang, H; Wang, H; Zhou, Y; Wang, E; Marincola, F M; Mai, C; Chen, Y; Wei, H; Song, Y; Lyu, X; Ye, Y; Cai, L; Wu, Q; Zhao, M; Hua, S; Fu, Q; Zhang, Y; Yao, K; Liu, Z; Li, X; Fang, W

    2013-05-16

    Connective tissue growth factor (CTGF) has different roles in different types of cancer. However, the involvement and molecular basis of CTGF in tumor progression and prognosis of human nasopharyngeal carcinoma (NPC) have almost never been reported. In this study, we observed that downregulated CTGF expression was significantly associated with NPC progression and poor prognosis. Knockdown of CTGF markedly elevated the ability of cell proliferation in vivo and in vitro. Subsequently, we discovered that the reduction of CTGF increased the expression of miR-18b, an oncomir-promoting cell proliferation. Further, we discovered that attenuated CTGF-mediated upregulation of miR-18b was dependent on the increased binding of transcription factors Jun proto-oncogene (C-Jun) and v-Myc myelocytomatosis viral oncogene homolog (C-Myc) to miR-18b promoter region via phosphoinositide 3-kinase (PI3K)/AKT pathway. Finally, we further found that miR-18b directly suppressed the expression of CTGF in NPC. In clinical fresh specimens, miR-18b was widely overexpressed and inversely correlated with CTGF expression in NPC. Our studies are the first to demonstrate that reduced CTGF as an unfavorable prognosis factor mediates the activation of miR-18b, an oncomir directly suppresses CTGF expression, by PI3K/AKT/C-Jun and C-Myc and promotes cell growth of NPC.

  10. DNA repair in the c-myc proto-oncogene locus: Possible involvement in susceptibility or resistance to plasmacytoma induction in BALB/c mice

    International Nuclear Information System (INIS)

    Beecham, E.J.; Mushinski, J.F.; Shacter, E.; Potter, M.; Bohr, V.A.

    1991-01-01

    This report describes an unexpected difference in the efficiency of removal of UV-induced DNA damage in the c-myc locus in splenic B lymphoblasts from two inbred strains of mice. In cells from plasmacytoma-resistant DBA/2N mice, 35% of UV-induced damage in the regulatory and 5' flank of c-myc is removed by 12 h. However, in cells from plasmacytoma-susceptible BALB/cAn mice, damage is not removed from this region. In the protein-encoding region and 3' flank of c-myc as well as in two dihydrofolate reductase gene fragments, UV damage is repaired with similar efficiency in B lymphoblasts from both strains of mice. Furthermore, in the protein-encoding portion and 3' flank of c-myc, damage is selectively removed from only the transcribed strand. No repair is detected in the nontranscribed strand. In contrast, DNA repair in the 5' flank of c-myc is not strand specific; in DNA from DBA/2N cells, UV damage is rapidly removed from both the transcribed and nontranscribed strands. In BALB/cAn cells no repair was detected in either strand in the 5'flank, consistent with the results with double-stranded, nick-translated probes to this region of c-myc. In addition to the repair studies, we have detected post-UV-damage formation: in most of the genes studied, we find that additional T4 endonuclease-sensitive sites are formed in the DNA 2 h after irradiation. Our findings provide new insights into the details of gene-specific and strand-specific DNA repair and suggest that there may be close links between DNA repair and B-cell neoplastic development

  11. Lipopolysaccharide stimulates endogenous β-glucuronidase via PKC/NF-κB/c-myc signaling cascade: a possible factor in hepatolithiasis formation.

    Science.gov (United States)

    Yao, Dianbo; Dong, Qianze; Tian, Yu; Dai, Chaoliu; Wu, Shuodong

    2017-11-29

    Hepatolithiasis is commonly encountered in Southeastern and Eastern Asian countries, but the pathogenesis mechanism of stone formation is still not well understood. Now, the role of endogenous β-glucuronidase in pigment stones formation is being gradually recognized. In this study, the mechanism of increased expression and secretion of endogenous β-glucuronidase during hepatolithiasis formation was investigated. We assessed the endogenous β-glucuronidase, c-myc, p-p65, and p-PKC expression in liver specimens with hepatolithiasis by immunohistochemical staining, and found that compared with that in normal liver samples, the expression of endogenous β-glucuronidase, c-myc, p-p65, and p-PKC in liver specimens with hepatolithiasis significantly increased, and their expressions were positively correlated with each other. Lipopolysaccharide (LPS) induced increased expression of endogenous β-glucuronidase and c-myc in hepatocytes and intrahepatic biliary epithelial cells in a dose- and time-dependent manner, and endogenous β-glucuronidase secretion increased, correspondingly. C-myc siRNA transfection effectively inhibited the LPS-induced expression of endogenous β-glucuronidase. Furthermore, NF-κB inhibitor pyrrolidine dithiocarbamate or PKC inhibitor chelerythrine could effectively inhibit the LPS-induced expression of c-myc and endogenous β-glucuronidase, and the expression of p-p65 was also partly inhibited by chelerythrine. Our clinical observations and experimental data indicate that LPS could induce the increased expression and secretion of endogenous β-glucuronidase via a signaling cascade of PKC/NF-κB/c-myc in hepatocytes and intrahepatic biliary epithelial cells, and endogenous β-glucuronidase might play a possible role in the formation of hepatolithiasis.

  12. Silencing c-Myc translation as a therapeutic strategy through targeting PI3Kδ and CK1ε in hematological malignancies.

    Science.gov (United States)

    Deng, Changchun; Lipstein, Mark R; Scotto, Luigi; Jirau Serrano, Xavier O; Mangone, Michael A; Li, Shirong; Vendome, Jeremie; Hao, Yun; Xu, Xiaoming; Deng, Shi-Xian; Realubit, Ronald B; Tatonetti, Nicholas P; Karan, Charles; Lentzsch, Suzanne; Fruman, David A; Honig, Barry; Landry, Donald W; O'Connor, Owen A

    2017-01-05

    Phosphoinositide 3-kinase (PI3K) and the proteasome pathway are both involved in activating the mechanistic target of rapamycin (mTOR). Because mTOR signaling is required for initiation of messenger RNA translation, we hypothesized that cotargeting the PI3K and proteasome pathways might synergistically inhibit translation of c-Myc. We found that a novel PI3K δ isoform inhibitor TGR-1202, but not the approved PI3Kδ inhibitor idelalisib, was highly synergistic with the proteasome inhibitor carfilzomib in lymphoma, leukemia, and myeloma cell lines and primary lymphoma and leukemia cells. TGR-1202 and carfilzomib (TC) synergistically inhibited phosphorylation of the eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1), leading to suppression of c-Myc translation and silencing of c-Myc-dependent transcription. The synergistic cytotoxicity of TC was rescued by overexpression of eIF4E or c-Myc. TGR-1202, but not other PI3Kδ inhibitors, inhibited casein kinase-1 ε (CK1ε). Targeting CK1ε using a selective chemical inhibitor or short hairpin RNA complements the effects of idelalisib, as a single agent or in combination with carfilzomib, in repressing phosphorylation of 4E-BP1 and the protein level of c-Myc. These results suggest that TGR-1202 is a dual PI3Kδ/CK1ε inhibitor, which may in part explain the clinical activity of TGR-1202 in aggressive lymphoma not found with idelalisib. Targeting CK1ε should become an integral part of therapeutic strategies targeting translation of oncogenes such as c-Myc. © 2017 by The American Society of Hematology.

  13. Nucleolus disassembly in mitosis and apoptosis: dynamic redistribution of phosphorylated-c-Myc, fibrillarin and Ki-67

    Directory of Open Access Journals (Sweden)

    C Soldani

    2009-06-01

    Full Text Available The nucleolus may undergo disassembly either reversibly during mitosis, or irreversibly in apoptosis, thus allowing the redistribution of the nucleolar proteins.We investigated here by immunocytochemistry the fate of three representative proteins, namely phosphorylated c-Myc, fibrillarin and Ki-67, and found that they behave independently in both processes: they relocate in distinct compartments during mitosis, whereas during apoptosis they may either be cleaved (Ki-67 or be extruded into the cytoplasm with a different kinetics and following an ordered, non chaotic program. The separation of these nucleolar proteins which occurs in early apoptotic nuclei continues also in the cytoplasm, and culminates in the final formation of apoptotic blebs containing different nucleolar proteins: this evidence confirms that the apoptotic bodies may be variable in size, content and surface reactivity, and include heterogeneous aggregates of nuclear proteins and/or nucleic acids.

  14. Correlation between Urothelial Differentiation and Sensory Proteins P2X3, P2X5, TRPV1, and TRPV4 in Normal Urothelium and Papillary Carcinoma of Human Bladder

    Directory of Open Access Journals (Sweden)

    Igor Sterle

    2014-01-01

    Full Text Available Terminal differentiation of urothelium is a prerequisite for blood-urine barrier formation and enables normal sensory function of the urinary bladder. In this study, urothelial differentiation of normal human urothelium and of low and high grade papillary urothelial carcinomas was correlated with the expression and localization of purinergic receptors (P2X3, and P2X5 and transient receptor potential vanilloid channels (TRPV1, and TRPV4. Western blotting and immunofluorescence of uroplakins together with scanning electron microscopy of urothelial apical surface demonstrated terminal differentiation of normal urothelium, partial differentiation of low grade carcinoma, and poor differentiation of high grade carcinoma. P2X3 was expressed in normal urothelium as well as in low grade carcinoma and in both cases immunolabeling was stronger in the superficial cells. P2X3 expression decreased in high grade carcinoma. P2X5 expression was detected in normal urothelium and in high grade carcinoma, while in low grade carcinoma its expression was diminished. The expression of TRPV1 decreased in low grade and even more in high grade carcinoma when compared with normal urothelium, while TRPV4 expression was unchanged in all samples. Our results suggest that sensory proteins P2X3 and TRPV1 are in correlation with urothelial differentiation, while P2X5 and TRPV4 have unique expression patterns.

  15. Wnt and Notch signaling pathway involved in wound healing by targeting c-Myc and Hes1 separately.

    Science.gov (United States)

    Shi, Yan; Shu, Bin; Yang, Ronghua; Xu, Yingbin; Xing, Bangrong; Liu, Jian; Chen, Lei; Qi, Shaohai; Liu, Xusheng; Wang, Peng; Tang, Jinming; Xie, Julin

    2015-06-16

    Wnt and Notch signaling pathways are critically involved in relative cell fate decisions within the development of cutaneous tissues. Moreover, several studies identified the above two pathways as having a significant role during wound healing. However, their biological effects during cutaneous tissues repair are unclear. We employed a self-controlled model (Sprague-Dawley rats with full-thickness skin wounds) to observe the action and effect of Wnt/β-catenin and Notch signalings in vivo. The quality of wound repair relevant to the gain/loss-of-function Wnt/β-catenin and Notch activation was estimated by hematoxylin-and-eosin and Masson staining. Immunofluorescence analysis and Western blot analysis were used to elucidate the underlying mechanism of the regulation of Wnt and Notch signaling pathways in wound healing. Meanwhile, epidermal stem cells (ESCs) were cultured in keratinocyte serum-free medium with Jaggedl or in DAPT (N-[(3,5-difluorophenyl)acetyl]-L-alanyl-2-phenyl]glycine-1,1-dimethylethyl) to investigate whether the interruption of Notch signaling contributes to the expression of Wnt/β-catenin signaling. The results showed that in vivo the gain-of-function Wnt/β-catenin and Notch activation extended the ability to promote wound closure. We further determined that activation or inhibition of Wnt signaling and Notch signaling can affect the proliferation of ESCs, the differentiation and migration of keratinocytes, and follicle regeneration by targeting c-Myc and Hes1, which ultimately lead to enhanced or delayed wound healing. Furthermore, Western blot analysis suggested that the two pathways might interact in vivo and in vitro. These results suggest that Wnt and Notch signalings play important roles in cutaneous repair by targeting c-Myc and Hes1 separately. What's more, interaction between the above two pathways might act as a vital role in regulation of wound healing.

  16. The TLR3/TICAM-1 signal constitutively controls spontaneous polyposis through suppression of c-Myc in Apc Min/+ mice.

    Science.gov (United States)

    Ono, Junya; Shime, Hiroaki; Takaki, Hiromi; Takashima, Ken; Funami, Kenji; Yoshida, Sumito; Takeda, Yohei; Matsumoto, Misako; Kasahara, Masanori; Seya, Tsukasa

    2017-10-17

    Intestinal tumorigenesis is promoted by myeloid differentiation primary response gene 88 (MyD88) activation in response to the components of microbiota in Apc Min/+ mice. Microbiota also contains double-stranded RNA (dsRNA), a ligand for TLR3, which activates the toll-like receptor adaptor molecule 1 (TICAM-1, also known as TRIF) pathway. We established Apc Min/+ Ticam1 -/- mice and their survival was compared to survival of Apc Min/+ Myd88 -/- and wild-type (WT) mice. The properties of polyps were investigated using immunofluorescence staining and RT-PCR analysis. We demonstrate that TICAM-1 is essential for suppression of polyp formation in Apc Min/+ mice. TICAM-1 knockout resulted in shorter survival of mice compared to WT mice or mice with knockout of MyD88 in the Apc Min/+ background. Polyps were more frequently formed in the distal intestine of Apc Min/+ Ticam1 -/- mice than in Apc Min/+ mice. Infiltration of immune cells such as CD11b + and CD8α + cells into the polyps was detected histologically. CD11b and CD8α mRNAs were increased in polyps of Apc Min/+ Ticam1 -/- mice compared to Apc Min/+ mice. Gene expression of inducible nitric oxide synthase (iNOS), interferon (IFN)-γ, CXCL9 and IL-12p40 was increased in polyps of Apc Min/+ Ticam1 -/- mice. mRNA and protein expression of c-Myc, a critical transcription factor for inflammation-associated polyposis, were increased in polyps of Apc Min/+ Ticam1 -/- mice. A Lactobacillus strain producing dsRNA was detected in feces of Apc Min/+ mice. These results imply that the TLR3/TICAM-1 pathway inhibits polyposis through suppression of c-Myc expression and supports long survival in Apc Min/+ mice.

  17. Mechanisms for c-myc Induced Mouse Mammary Gland Carcinogenesis and for the Synergistic Role of TGF(alpha) in the Process

    Science.gov (United States)

    2001-07-01

    1242 11-28. anti-tumor effects with microencapsulated c-myc antisense Panico L, D’Antonio A, Salvatore G, Mezza E, Tortora G, De oligonucleotide... enzymatic conversion of androgens to estrogens, since an estrogen receptor antagonist cannot block the lobular- alveolar induction by T, DHT

  18. Course of c-myc mRNA expression in the regenerating mouse testis determined by competitive reverse transcriptase polymerase chain reaction.

    Science.gov (United States)

    Amendola, R

    1994-11-01

    The c-myc proto-oncogene is a reliable marker of the "G0-early G1" transition, and its down-regulation is believed to be necessary to obtain cellular differentiation. In murine spermatogenesis, the level of c-myc transcripts does not correlate with the rate of cellular division. Proliferation of supposed staminal spermatogonia to reproduce themselves is induced with a local 5 Gy X-ray dose in 90-day-old C57Bl/6 mice. c-myc quantification by a newly developed competitive reverse transcriptase polymerase chain reaction (RT-PCR) was carried out to follow the expression course of this proto-oncogene. Damage and restoration of spermatogenesis were analyzed at days 3, 6, 9, 10, 13, 30, and 60 after injury by relative testes/body weight determination and histological examination. Proliferative status was determined by histone H3 Northern blot analysis. c-myc mRNA level was 10 times higher after 3 days in the irradiated animals compared to the controls. An increasing number of copies were noted up to 10 days, but promptly decreased to the base level found for irradiated mice from 13 to 60 days. Interestingly, the expression of histone H3 detected S phase only in testes at 60 days from damage.

  19. [Relationship between the expression of beta-cat, cyclin D1 and c-myc and the occurance and biological behavior of pancreatic cancer].

    Science.gov (United States)

    Li, Yu-jun; Ji, Xiang-rui

    2003-06-01

    To study the relationship between the abnormal expression of beta-catenin (beta-cat) and the high expressions of cyclin D1 and c-myc and the occurance, proliferation, infiltration, metastasis and prognosis of pancreatic cancer, and to provide rational basis for the clinical diagnosis and treatment. Immunohistochemical PicTure trade mark was used to examine the expressions of beta-cat, cyclin D1 and c-myc in 47 cases of the cancerous tissue of pancreas, 12 cases of the pancreatic intraepithelial neoplasia and 10 cases of normal tissue of pancreas, respectively. Pancreatic cancer proliferation cell nuclear antigen (PCNA) was also tested as the index of the extent of proliferation of the pancreatic cancer. beta-cat was expressed normally in the 10 cases of the normal pancreatic tissue, while cyclin D1 and c-myc were negative. The expression rates of beta-cat, cyclin D1 and c-myc in the tissues of the pancreatic intraepithelial neoplasia and the pancreatic cancer had no significant difference [6/12 and 68.1% (32/47), 6/12 and 74.5% (35/47), 5/12 and 70.2% (33/47) respectively;P values were all more than 0.05]. The abnormal expression rate of beta-cat was significantly correlated to the metastasis of the pancreatic cancer and the one-year survival rate (both P 0.05). The expression rate of cyclin D1 was correlated with the proliferation of the pancreatic cancer and the extent of differentiation (both P 0.05). The expression rate of c-myc was not correlated with the size, the extent of proliferation, infiltration, metastasis, or one-year survival rate (both P > 0.05), but closely with the proliferation activity of the cancerous tissue of pancreas (P < 0.05). The abnormal expression of beta-cat and the high expressions of cyclin D1 and c-myc had a parallel relationship with the pancreatic intraepithelial neoplasia and pancreatic cancer (both P < 0.05, gamma = 1.000, 0.845, 0.437, 0.452). The abnormal expression of beta-cat activates cyclin D1 and c-myc, and results in the

  20. Targeting of the MYCN Protein with Small Molecule c-MYC Inhibitors

    OpenAIRE

    Müller, Inga; Larsson, Karin; Frenzel, Anna; Oliynyk, Ganna; Zirath, Hanna; Prochownik, Edward V.; Westwood, Nicholas J.; Henriksson, Marie Arsenian

    2014-01-01

    This study was funded by grants from the Swedish Research Council and the Swedish Cancer Society. IM and HZ were recipients of graduate student grants from KI (KID), MAH was recipient of a Senior Investigator Award from the Swedish Cancer Society, and NJW was a Royal Society University Research Fellow when this work began. Members of the MYC family are the most frequently deregulated oncogenes in human cancer and are often correlated with aggressive disease and/or poorly differentiated tum...

  1. Study of C-MYC amplification and expression in Iranian gastric cancer samples using CISH and IHC methods.

    Science.gov (United States)

    Khaleghian, Malihea; Jahanzad, Issa; Shakoori, Abbas; Ardalan, Farid Azmoudeh; Azimi, Cyrus

    2015-01-01

    Gastric cancer is the fourth most frequent malignancy and the second cause of cancer-related mortality worldwide. It has been suggested that in gastric carcinogenesis, the C-MYC gene has an important function. The objective of this study is to establish the preference of Chromogenic in situ hybridization (CISH) and Immunohistochemistry (IHC) in the diagnosis and prognosis of gastric cancer. Samples comprised of 50 randomly selected patients of whom 40 were male and 10 female. To evaluate the MYC copy number and its protein expression, CISH and IHC analyses were performed for 50 gastric adenocarcinomas, in Iran. The location of the tumor in 64% of the patients was the fundus, and in 72% of patients, the tumors were of a diffuse type; 22 samples showed no amplification, and 28 samples were with amplification. MYC immunoreactivity was observed in 13 samples. Twelve samples showed both MYC amplification and MYC immunoreactivity. In addition, among the 28 CISH+ samples, 12 samples had positive signals for IHC and 16 samples had negative signals for IHC. A majority of the IHC-negative patients had no amplification, but only one patient with IHC positive had no amplification. Our conclusion was that for the management and treatment of gastric cancer, and for special attention of clinicians, for prognosis and tumor progression, the CISH was a better and more feasible test than IHC, in regard to the sensitivity and specificity.

  2. Study of C-MYC amplification and expression in Iranian gastric cancer samples using CISH and IHC methods

    Directory of Open Access Journals (Sweden)

    Malihea Khaleghian

    2015-01-01

    Full Text Available Background: Gastric cancer is the fourth most frequent malignancy and the second cause of cancer-related mortality worldwide. It has been suggested that in gastric carcinogenesis, the C-MYC gene has an important function. The objective of this study is to establish the preference of Chromogenic in situ hybridization (CISH and Immunohistochemistry (IHC in the diagnosis and prognosis of gastric cancer. Materials and Methods: Samples comprised of 50 randomly selected patients of whom 40 were male and 10 female. To evaluate the MYC copy number and its protein expression, CISH and IHC analyses were performed for 50 gastric adenocarcinomas, in Iran. Results: The location of the tumor in 64% of the patients was the fundus, and in 72% of patients, the tumors were of a diffuse type; 22 samples showed no amplification, and 28 samples were with amplification. MYC immunoreactivity was observed in 13 samples. Twelve samples showed both MYC amplification and MYC immunoreactivity. In addition, among the 28 CISH+ samples, 12 samples had positive signals for IHC and 16 samples had negative signals for IHC. A majority of the IHC-negative patients had no amplification, but only one patient with IHC positive had no amplification. Conclusion: Our conclusion was that for the management and treatment of gastric cancer, and for special attention of clinicians, for prognosis and tumor progression, the CISH was a better and more feasible test than IHC, in regard to the sensitivity and specificity.

  3. Association Between Amplification and Expression of C-MYC Gene and Clinicopathological Characteristics of Stomach Cancer.

    Science.gov (United States)

    Khaleghian, Malihea; Jahanzad, Issa; Shakoori, Abbas; Emami Razavi, Amirnader; Azimi, Cyrus

    2016-02-01

    The incidence rate of gastric cancer in western countries has shown a remarkable decline in the recent years while it is still the most common cancer among males in Iran. The proto-oncogene MYC, located at 8q24.1, regulates almost 15% of human genes and is activated in 20% of all tumors. The amplification of MYC and overexpression of its protein product are observed in 15 - 30% of gastric neoplasias. The objective of this study was to find the preferences of Chromogenic In Situ Hybridization (CISH) and Immunohistochemistry (IHC) in diagnosis and prognosis of gastric cancer. We studied 102 samples of gastric cancer in Iran and all the patients had undergone primary surgical resection at the Cancer Institute Hospital, Tehran University of Medical Sciences. The CISH and IHC techniques were applied for all our samples. All of the samples had adenocarcinoma gastric cancer and were selected randomly. Also, the type of study was cross sectional. The sample size was 100 patients. Our data revealed that both diffuse and intestinal types of gastric cancer occurred significantly more in males than females. Our results showed that there was an indication of some correlation between grades and CISH, although the difference was not significant. Our data also showed that CISH positive patients (43%) were more frequent compared to IHC positive patients (14.7%). There was a correlation between CISH and IHC. These results revealed that there was a significant difference between grades and IHC. There was also no statistical difference between CISH amplification in diffuse and intestinal types. From the results, it could be concluded that for administration of the treatment of stomach cancer, and progress and prognosis of tumor, which is important for patients and clinicians, the CISH is a better and more feasible test than IHC, in regards to sensitivity and specificity.

  4. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yuexia [Institute of Radiation Medicine, Fudan University, Shanghai (China); Central Laboratory, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen [Institute of Radiation Medicine, Fudan University, Shanghai (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

    2015-02-15

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  5. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    International Nuclear Information System (INIS)

    Xie, Yuexia; Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen; Shao, Chunlin

    2015-01-01

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved

  6. Regulation of c-myc and c-fos mRNA levels by polyomavirus: distinct roles for the capsid protein VP1 and the viral early proteins

    International Nuclear Information System (INIS)

    Zullo, J.; Stiles, C.D.; Garcea, R.L.

    1987-01-01

    The levels of c-myc, c-fos, and JE mRNAs accumulate in a biphasic pattern following infection of quiescent BALB/c 3T3 mouse cells with polyomavirus. Maximal levels of c-myc and c-fos mRNAs were seen within 1 hr and were nearly undetectable at 6 hr after infection. At 12 hr after infection mRNA levels were again maximal and remained elevated thereafter. Empty virions (capsids) and recombinant VP 1 protein, purified from Escherichia coli, induced the early but not the late phase of mRNA accumulation. Virions, capsids, and recombinant VP 1 protein stimulated [ 3 H]thymidine nuclear labeling and c-myc mRNA accumulation in a dose-responsive manner paralleling their affinity for the cell receptor for polyoma. The second phase of mRNA accumulation is regulated by the viral early gene products, as shown by polyomavirus early gene mutants and by a transfected cell line (336a) expressing middle tumor antigen upon glucocorticoid addition. These results suggest that polyomavirus interacts with the cell membrane at the onset of infection to increase the levels of mRNA for the cellular genes associated with cell competence for DNA replication, and subsequently these levels are maintained by the action of the early viral proteins

  7. Aspirin regulation of c-myc and cyclinD1 proteins to overcome tamoxifen resistance in estrogen receptor-positive breast cancer cells.

    Science.gov (United States)

    Cheng, Ran; Liu, Ya-Jing; Cui, Jun-Wei; Yang, Man; Liu, Xiao-Ling; Li, Peng; Wang, Zhan; Zhu, Li-Zhang; Lu, Si-Yi; Zou, Li; Wu, Xiao-Qin; Li, Yu-Xia; Zhou, You; Fang, Zheng-Yu; Wei, Wei

    2017-05-02

    Tamoxifen is still the most commonly used endocrine therapy drug for estrogen receptor (ER)-positive breast cancer patients and has an excellent outcome, but tamoxifen resistance remains a great impediment to successful treatment. Recent studies have prompted an anti-tumor effect of aspirin. Here, we demonstrated that aspirin not only inhibits the growth of ER-positive breast cancer cell line MCF-7, especially when combined with tamoxifen, but also has a potential function to overcome tamoxifen resistance in MCF-7/TAM. Aspirin combined with tamoxifen can down regulate cyclinD1 and block cell cycle in G0/G1 phase. Besides, tamoxifen alone represses c-myc, progesterone receptor (PR) and cyclinD1 in MCF-7 cell line but not in MCF-7/TAM, while aspirin combined with tamoxifen can inhibit the expression of these proteins in the resistant cell line. When knocking down c-myc in MCF-7/TAM, cells become more sensitive to tamoxifen, cell cycle is blocked as well, indicating that aspirin can regulate c-myc and cyclinD1 proteins to overcome tamoxifen resistance. Our study discovered a novel role of aspirin based on its anti-tumor effect, and put forward some kinds of possible mechanisms of tamoxifen resistance in ER-positive breast cancer cells, providing a new strategy for the treatment of ER-positive breast carcinoma.

  8. Cyclin E/Cdk2, P/CAF, and E1A regulate the transactivation of the c-myc promoter by FOXM1

    International Nuclear Information System (INIS)

    Wierstra, Inken; Alves, Juergen

    2008-01-01

    FOXM1c transactivates the c-myc promoter by binding directly to its TATA-boxes. The present study demonstrates that the transactivation of the c-myc promoter by FOXM1c is enhanced by the key proliferation signal cyclin E/Cdk2, but repressed by P/CAF and the adenoviral oncoprotein E1A. Furthermore, FOXM1c interacts with the coactivator and histone acetyltransferase P/CAF. This study shows that, on the c-myc-P1 TATA-box, FOXM1c does not function simply as normal transcription factor just binding to an unusual site. Moreover, the inhibitory N-terminus of FOXM1c does not inhibit its transrepression domain or its EDA. Others reported that a cyclin/Cdk-binding LXL-motif of the splice variant FoxM1b is required for its interaction with Cdk2, Cdk1, and p27, its phosphorylation by Cdk1 and its activation by Cdc25B. In contrast, we now demonstrate that this LXL-motif is not required for the activation of FOXM1c by cyclin D1/Cdk4, cyclin E/Cdk and cyclin A/Cdk2 or for the repression of FOXM1c by p27

  9. The Dysregulation of Polyamine Metabolism in Colorectal Cancer Is Associated with Overexpression of c-Myc and C/EBPβ rather than Enterotoxigenic Bacteroides fragilis Infection

    Directory of Open Access Journals (Sweden)

    Anastasiya V. Snezhkina

    2016-01-01

    Full Text Available Colorectal cancer is one of the most common cancers in the world. It is well known that the chronic inflammation can promote the progression of colorectal cancer (CRC. Recently, a number of studies revealed a potential association between colorectal inflammation, cancer progression, and infection caused by enterotoxigenic Bacteroides fragilis (ETBF. Bacterial enterotoxin activates spermine oxidase (SMO, which produces spermidine and H2O2 as byproducts of polyamine catabolism, which, in turn, enhances inflammation and tissue injury. Using qPCR analysis, we estimated the expression of SMOX gene and ETBF colonization in CRC patients. We found no statistically significant associations between them. Then we selected genes involved in polyamine metabolism, metabolic reprogramming, and inflammation regulation and estimated their expression in CRC. We observed overexpression of SMOX, ODC1, SRM, SMS, MTAP, c-Myc, C/EBPβ (CREBP, and other genes. We found that two mediators of metabolic reprogramming, inflammation, and cell proliferation c-Myc and C/EBPβ may serve as regulators of polyamine metabolism genes (SMOX, AZIN1, MTAP, SRM, ODC1, AMD1, and AGMAT as they are overexpressed in tumors, have binding site according to ENCODE ChIP-Seq data, and demonstrate strong coexpression with their targets. Thus, increased polyamine metabolism in CRC could be driven by c-Myc and C/EBPβ rather than ETBF infection.

  10. UDP/P2Y6 receptor signaling regulates IgE-dependent degranulation in human basophils

    Directory of Open Access Journals (Sweden)

    Manabu Nakano

    2017-10-01

    Conclusions: This study showed that UDP/P2Y6 receptor signaling is involved in the regulation of IgE-dependent degranulation in basophils, which might stimulate the P2Y6 receptor via the autocrine secretion of UTP. Thus, this receptor represents a potential target to regulate IgE-dependent degranulation in basophils during allergic diseases.

  11. An intact PDZ motif is essential for correct P2Y12 purinoceptor traffic in human platelets.

    Science.gov (United States)

    Nisar, Shaista; Daly, Martina E; Federici, Augusto B; Artoni, Andrea; Mumford, Andrew D; Watson, Stephen P; Mundell, Stuart J

    2011-11-17

    The platelet P2Y(12) purinoceptor (P2Y(12)R), which plays a crucial role in hemostasis, undergoes internalization and subsequent recycling to maintain receptor responsiveness, processes that are essential for normal platelet function. Here, we observe that P2Y(12)R function is compromised after deletion or mutation of the 4 amino acids at the extreme C-terminus of this receptor (ETPM), a putative postsynaptic density 95/disc large/zonula occludens-1 (PDZ)-binding motif. In cell line models, removal of this sequence or mutation of one of its core residues (P341A), attenuates receptor internalization and receptor recycling back to the membrane, thereby blocking receptor resensitization. The physiologic significance of these findings in the regulation of platelet function is shown by identification of a patient with a heterozygous mutation in the PDZ binding sequence of their P2Y(12)R (P341A) that is associated with reduced expression of the P2Y(12)R on the cell surface. Importantly, platelets from this subject showed significantly compromised P2Y(12)R recycling, emphasizing the importance of the extreme C-terminus of this receptor to ensure correct receptor traffic.

  12. The human T-cell leukemia virus type-1 p30II protein activates p53 and induces the TIGAR and suppresses oncogene-induced oxidative stress during viral carcinogenesis.

    Science.gov (United States)

    Romeo, Megan; Hutchison, Tetiana; Malu, Aditi; White, Averi; Kim, Janice; Gardner, Rachel; Smith, Katie; Nelson, Katherine; Bergeson, Rachel; McKee, Ryan; Harrod, Carolyn; Ratner, Lee; Lüscher, Bernhard; Martinez, Ernest; Harrod, Robert

    2018-05-01

    In normal cells, aberrant oncogene expression leads to the accumulation of cytotoxic metabolites, including reactive oxygen species (ROS), which can cause oxidative DNA-damage and apoptosis as an intrinsic barrier against neoplastic disease. The c-Myc oncoprotein is overexpressed in many lymphoid cancers due to c-myc gene amplification and/or 8q24 chromosomal translocations. Intriguingly, p53 is a downstream target of c-Myc and hematological malignancies, such as adult T-cell leukemia/lymphoma (ATL), frequently contain wildtype p53 and c-Myc overexpression. We therefore hypothesized that p53-regulated pro-survival signals may thwart the cell's metabolic anticancer defenses to support oncogene-activation in lymphoid cancers. Here we show that the Tp53-induced glycolysis and apoptosis regulator (TIGAR) promotes c-myc oncogene-activation by the human T-cell leukemia virus type-1 (HTLV-1) latency-maintenance factor p30 II , associated with c-Myc deregulation in ATL clinical isolates. TIGAR prevents the intracellular accumulation of c-Myc-induced ROS and inhibits oncogene-induced cellular senescence in ATL, acute lymphoblastic leukemia, and multiple myeloma cells with elevated c-Myc expression. Our results allude to a pivotal role for p53-regulated antioxidant signals as mediators of c-Myc oncogenic functions in viral and non-viral lymphoid tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. The p2 domain of human immunodeficiency virus type 1 Gag regulates sequential proteolytic processing and is required to produce fully infectious virions.

    Science.gov (United States)

    Pettit, S C; Moody, M D; Wehbie, R S; Kaplan, A H; Nantermet, P V; Klein, C A; Swanstrom, R

    1994-12-01

    The proteolytic processing sites of the human immunodeficiency virus type 1 (HIV-1) Gag precursor are cleaved in a sequential manner by the viral protease. We investigated the factors that regulate sequential processing. When full-length Gag protein was digested with recombinant HIV-1 protease in vitro, four of the five major processing sites in Gag were cleaved at rates that differ by as much as 400-fold. Three of these four processing sites were cleaved independently of the others. The CA/p2 site, however, was cleaved approximately 20-fold faster when the adjacent downstream p2/NC site was blocked from cleavage or when the p2 domain of Gag was deleted. These results suggest that the presence of a C-terminal p2 tail on processing intermediates slows cleavage at the upstream CA/p2 site. We also found that lower pH selectively accelerated cleavage of the CA/p2 processing site in the full-length precursor and as a peptide primarily by a sequence-based mechanism rather than by a change in protein conformation. Deletion of the p2 domain of Gag results in released virions that are less infectious despite the presence of the processed final products of Gag. These findings suggest that the p2 domain of HIV-1 Gag regulates the rate of cleavage at the CA/p2 processing site during sequential processing in vitro and in infected cells and that p2 may function in the proper assembly of virions.

  14. Distinct Histopathologic and Molecular Alterations in Inflammatory Bowel Disease-Associated Intestinal Adenocarcinoma: c-MYC Amplification is Common and Associated with Mucinous/Signet Ring Cell Differentiation.

    Science.gov (United States)

    Hartman, Douglas J; Binion, David G; Regueiro, Miguel D; Miller, Caitlyn; Herbst, Cameron; Pai, Reetesh K

    2018-05-17

    Chronic idiopathic inflammatory bowel disease (IBD) is a significant risk factor for the development of intestinal adenocarcinoma. The underlying molecular alterations in IBD-associated intestinal adenocarcinoma remain largely unknown. We compared the clinicopathologic and molecular features of 35 patients with 47 IBD-associated intestinal adenocarcinomas with a consecutive series of 451 patients with sporadic colorectal carcinoma identified at our institution and published data on sporadic colorectal carcinoma. c-MYC amplification was the most frequent molecular alteration identified in 33% of IBD-associated intestinal adenocarcinoma that is a significantly higher frequency than in sporadic colorectal carcinoma (8%) (P = 0.0001). Compared to sporadic colorectal carcinoma, IBD-associated intestinal adenocarcinomas more frequently demonstrated mucinous differentiation (60% vs 25%, P < 0.001) and signet ring cell differentiation (28% vs 4%, P < 0.001). Mucinous and signet ring cell differentiation were significantly associated with the presence of c-MYC amplification (both with P < 0.05). HER2 positivity (11%), KRAS exon 2 or 3 mutation (10%), and IDH1 mutation (7%) were less commonly observed in IBD-associated intestinal adenocarcinoma. There was an association between poor survival and HER2 status with 3 of 4 patients having HER2-positive adenocarcinoma dead of disease at last clinical follow-up; however, no statistically significant survival effect was identified for any of the molecular alterations identified. We demonstrate that IBD-associated intestinal adenocarcinomas have a high frequency of c-MYC amplification that is associated with mucinous and signet ring cell differentiation. Many of the identified molecular alterations have potential therapeutic relevance, including HER2 amplification, IDH1 mutation, and low frequency KRAS mutation.

  15. The subcellular distribution of the human ribosomal "stalk" components: P1, P2 and P0 proteins

    DEFF Research Database (Denmark)

    Tchórzewski, Marek; Krokowski, Dawid; Rzeski, Wojciech

    2003-01-01

    The ribosomal "stalk" structure is a distinct lateral protuberance located on the large ribosomal subunit in prokaryotic, as well as in eukaryotic cells. In eukaryotes, this ribosomal structure is composed of the acidic ribosomal P proteins, forming two hetero-dimers (P1/P2) attached...

  16. cMyc/miR-125b-5p signalling determines sensitivity to bortezomib in preclinical model of cutaneous T-cell lymphomas

    DEFF Research Database (Denmark)

    Manfè, Valentina; Biskup, Edyta; Willumsgaard, Ayalah

    2013-01-01

    Successful/effective cancer therapy in low grade lymphoma is often hampered by cell resistance to anti-neoplastic agents. The crucial mechanisms responsible for this phenomenon are poorly understood. Overcoming resistance of tumor cells to anticancer agents, such as proteasome inhibitors, could...... improve their clinical efficacy. Using cutaneous T-cell lymphoma (CTCL) as a model of the chemotherapy-resistant peripheral lymphoid malignancy, we demonstrated that resistance to proteasome inhibition involved a signaling between the oncogene cMyc and miR-125b-5p. Bortezomib repressed c...

  17. Increased radiation-induced transformation in C3H/10T1/2 cells after transfer of an exogenous c-myc gene

    International Nuclear Information System (INIS)

    Sorrentino, V.; Drozdoff, V.; Zeitz, L.; Fleissner, E.

    1987-01-01

    C3H/10T 1/2 cells were infected with a retroviral vector expressing a mouse c-myc oncogene and a drug-selection marker. The resulting cells, morphologically indistinguishable from C3H/10T l/1, displayed a greatly enhanced sensitivity to neoplastic transformation by ionizing radiation or by a chemical carcinogen. Constitutive expression of myc therefore appears to synergize with an initial carcinogenic event, providing a function analogous to a subsequent event that apparently is required for the neoplastic transformation of these cells. This cell system should prove useful in exploring early stages in radiation-induced transformation

  18. Angiotensin II reduces cardiac AdipoR1 expression through AT1 receptor/ROS/ERK1/2/c-Myc pathway.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2 mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1 receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII.

  19. Overexpression of c-myc and loss of heterozigosity on 2p, 3p, 5q, 17p and 18q in sporadic colorectal carcinoma Sobreexpresión de c-myc y pérdida de heterozigosidad en 2p, 3p, 5q, 17p y 18q en carcinoma colorrectal esporádico

    Directory of Open Access Journals (Sweden)

    A. Sánchez-Pernaute

    2005-03-01

    Full Text Available Aim: the aim of the present study is to evaluate the prognostic influence of loss of heterozygosity on 2p, 3p, 5q, 17p and 18q, and c-myc overexpression on surgically treated sporadic colorectal carcinoma. Methods: tumor and non-tumor tissue samples from 153 patients were analyzed. Fifty-one percent of patients were male, and mean age in the series was 67 years. Tumors were located in the proximal colon in 37 cases, in the distal bowel in 37, and in the rectum in 79 patients. c-myc overexpression was studied by means of Northern blot analysis, and loss of heterozigosity through microsatellite analysis. Results: c-myc overexpression was detected in 25% of cases, and loss of heterozygosity in at least one of the studied regions in 48%. There was no association between clinical and pathologic features, and genetic alterations. The disease-free interval was significantly shorter for patients with both genetic alterations; the presence of both events was an independent prognostic factor for poor outcome in the multivariate analysis (RR: 4.34, p Objetivo: el objetivo del presente trabajo es evaluar la importancia pronóstica de la pérdida de heterozigosidad en las regiones 2p, 3p, 5q, 17p y 18q y de la sobreexpresión del gen c-myc en el carcinoma colorrectal esporádico, mediante el estudio de la supervivencia libre de enfermedad tras cirugía potencialmente curativa. Métodos: se han analizado muestras tumorales y no tumorales de mucosa colónica de 153 pacientes. El 51% de los pacientes eran varones y la edad media de la serie fue 67 años. Los tumores fueron proximales en 37 casos, distales en 37 y localizados en recto en 79. Se analizó la sobreexpresión del RNA de c-myc por Northern blot, y la presencia de pérdida de heterozigosidad en las diferentes regiones consideradas por análisis de microsatélites. Resultados: se detectó sobreexpresión de c-myc en el 25% de los casos, y pérdida de heterozigosidad en alguna de las regiones estudiadas

  20. The reducing agent Dithiothreitol (DTT) increases expression of c-myc and c- fos protooncogenes in human cells

    DEFF Research Database (Denmark)

    Skouv, J.; Sørensen, Ilona Kryspin; Frandsen, H.

    1995-01-01

    The objective of the present study was to assess the possible tumour promoting activity of the food mutagen 2-hydroxyamino-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhIP), by studying its influence on the expression of three genes considered to be of relevance in the tumour promotion step...

  1. Isolation and characterization of exosome from human embryonic stem cell-derived c-myc-immortalized mesenchymal stem cells

    NARCIS (Netherlands)

    Lai, Ruenn Chai; Yeo, Ronne Wee Yeh; Padmanabhan, Jayanthi; Choo, Andre; De Kleijn, Dominique P V; Lim, Sai Kiang

    2016-01-01

    Mesenchymal stem cells (MSC) are currently the cell type of choice in many cell therapy trials. The number of therapeutic applications for MSCs registered as product IND submissions with the FDA and initiation of registered clinical trials has increased substantially in recent years, in particular

  2. Isolation and Characterization of Exosome from Human Embryonic Stem Cell-Derived C-Myc-Immortalized Mesenchymal Stem Cells.

    Science.gov (United States)

    Lai, Ruenn Chai; Yeo, Ronne Wee Yeh; Padmanabhan, Jayanthi; Choo, Andre; de Kleijn, Dominique P V; Lim, Sai Kiang

    2016-01-01

    Mesenchymal stem cells (MSC) are currently the cell type of choice in many cell therapy trials. The number of therapeutic applications for MSCs registered as product IND submissions with the FDA and initiation of registered clinical trials has increased substantially in recent years, in particular between 2006 and 2012. However, defined mechanisms of action underpinning the therapeutic efficacy of MSCs are lacking, but they are increasingly attributed to MSC trophic secretion rather than their differentiation potential. A promising secreted therapeutic candidate is an extracellular vesicle (EV) known as the exosome. The use of exosomes instead of cells as a therapeutic agent provides several advantages. A critical advantage is the prospect of a conventional pharmaceutical manufacturing process that is highly scalable and amenable to the stringent manufacturing process. For example, MSCs used as producers of therapeutics, and not as therapeutics per se, could be immortalized to generate infinitely expansible clonal lines to enhance the reproducible production of therapeutic exosomes. In this chapter, we will describe the immortalization of MSCs, and the production, isolation, and characterization of exosomes from immortalized MSC.

  3. Dynamics of the Peripheral Membrane Protein P2 from Human Myelin Measured by Neutron Scattering--A Comparison between Wild-Type Protein and a Hinge Mutant.

    Directory of Open Access Journals (Sweden)

    Saara Laulumaa

    Full Text Available Myelin protein P2 is a fatty acid-binding structural component of the myelin sheath in the peripheral nervous system, and its function is related to its membrane binding capacity. Here, the link between P2 protein dynamics and structure and function was studied using elastic incoherent neutron scattering (EINS. The P38G mutation, at the hinge between the β barrel and the α-helical lid, increased the lipid stacking capacity of human P2 in vitro, and the mutated protein was also functional in cultured cells. The P38G mutation did not change the overall structure of the protein. For a deeper insight into P2 structure-function relationships, information on protein dynamics in the 10 ps to 1 ns time scale was obtained using EINS. Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared. Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale. Molecular dynamics simulations confirmed the enhanced dynamics of the mutant variant, especially within the portal region in the presence of bound fatty acid. The increased softness of the hinge mutant of human myelin P2 protein is likely related to an enhanced flexibility of the portal region of this fatty acid-binding protein, as well as to its interactions with the lipid bilayer surface requiring conformational adaptations.

  4. Characterization of a Ca2+ response to both UTP and ATP at human P2Y11 receptors: evidence for agonist-specific signaling.

    Science.gov (United States)

    White, Pamela J; Webb, Tania E; Boarder, Michael R

    2003-06-01

    Previous reports on heterologously-expressed human P2Y11 receptors have indicated that ATP, but not UTP, is an agonist stimulating both phosphoinositidase C and adenylyl cyclase. Consistent with these findings, we report that in 1321N1 cells expressing human P2Y11 receptors, UTP stimulation did not lead to accumulation of inositol(poly)phosphates under conditions in which ATP gave a robust, concentration-dependent effect. Unexpectedly, however, both UTP and ATP stimulated increases in cytosolic Ca2+ concentration ([Ca2+]c), with both nucleotides achieving similar EC50 and maximal responses. The responses to maximally effective concentrations of ATP and UTP were not additive. The [Ca2+]c increase in response to UTP was less dependent on extracellular Ca2+ than was the response to ATP. AR-C67085 (2-propylthio-beta,gamma-difluoromethylene-d-ATP, a P2Y11-selective agonist), adenosine 5'-O-(3-thiotriphosphate), and benzoyl ATP were all full agonists with potencies similar to those of ATP and UTP. In desensitization experiments, exposure to ATP resulted in loss of the UTP response; this response was more sensitive to desensitization than that of ATP. Pertussis toxin pretreatment attenuated the response to UTP but left the ATP response unaffected. The presence of 2-aminoethyl diphenylborate differentially affected the responses of ATP and UTP. No mRNA transcripts for P2Y2 or P2Y4 were detectable in the P2Y11-expressing cells. We conclude that UTP is a Ca2+-mobilizing agonist at P2Y11 receptors and that ATP and UTP acting at the same receptor recruit distinct signaling pathways. This example of agonist-specific signaling is discussed in terms of agonist trafficking and differential signal strength.

  5. Sp1/3 and NF-1 mediate basal transcription of the human P2X1 gene in megakaryoblastic MEG-01 cells

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    Ennion Steven J

    2006-03-01

    Full Text Available Abstract Background P2X1 receptors play an important role in platelet function as they can induce shape change, granule centralization and are also involved in thrombus formation. As platelets have no nuclei, the level of P2X1 expression depends on transcriptional regulation in megakaryocytes, the platelet precursor cell. Since nothing is known about the molecular mechanisms regulating megakaryocytic P2X1 expression, this study aimed to identify and functionally characterize the P2X1 core promoter utilized in the human megakaryoblastic cell line MEG-01. Results In order to identify cis-acting elements involved in the transcriptional regulation of P2X1 expression, the ability of 4.7 kb P2X1 upstream sequence to drive luciferase reporter gene expression was tested. Low promoter activity was detected in proliferating MEG-01 cells. This activity increased 20-fold after phorbol-12-myristate-13-acetate (PMA induced differentiation. A transcription start site was detected 365 bp upstream of the start codon by primer extension. Deletion analysis of reporter constructs indicated a core promoter located within the region -68 to +149 bp that contained two Sp1 sites (named Sp1a and Sp1b and an NF-1 site. Individual mutations of Sp1b or NF-1 binding sites severely reduced promoter activity whereas triple mutation of Sp1a, Sp1b and NF-1 sites completely abolished promoter activity in both untreated and PMA treated cells. Sp1/3 and NF-1 proteins were shown to bind their respective sites by EMSA and interaction of Sp1/3, NF-1 and TFIIB with the endogenous P2X1 core promoter in MEG-01 cells was demonstrated by chromatin immunoprecipitation. Alignment of P2X1 genes from human, chimp, rat, mouse and dog revealed consensus Sp1a, Sp1b and NF-1 binding sites in equivalent positions thereby demonstrating evolutionary conservation of these functionally important sites. Conclusion This study has identified and characterized the P2X1 promoter utilized in MEG-01 cells and

  6. Down-regulation of 5S rRNA by miR-150 and miR-383 enhances c-Myc-rpL11 interaction and inhibits proliferation of esophageal squamous carcinoma cells.

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    Wang, Xinyu; Ren, Yanli; Wang, Zhiqiong; Xiong, Xiangyu; Han, Sichong; Pan, Wenting; Chen, Hongwei; Zhou, Liqing; Zhou, Changchun; Yuan, Qipeng; Yang, Ming

    2015-12-21

    5S rRNA plays an important part in ribosome biology and is over-expression in multiple cancers. In this study, we found that 5S rRNA is a direct target of miR-150 and miR-383 in esophageal squamous cell carcinoma (ESCC). Overexpression of miR-150 and miR-383 inhibited ESCC cell proliferation in vitro and in vivo. Moreover, 5S rRNA silencing by miR-150 and miR-383 might intensify rpL11-c-Myc interaction, which attenuated role of c-Myc as an oncogenic transcriptional factor and dysregulation of multiple c-Myc target genes. Taken together, our results highlight the involvement of miRNAs in ribosomal regulation during tumorigenesis. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  7. Epithelial-to-mesenchymal transition and c-myc expression are the determinants of cetuximab-induced enhancement of squamous cell carcinoma radioresponse

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    Skvortsova, Ira; Skvortsov, Sergej; Raju, Uma; Stasyk, Taras; Riesterer, Oliver; Schottdorf, Eva-Maria; Popper, Bela-Andre; Schiestl, Bernhard; Eichberger, Paul; Debbage, Paul; Neher, Andreas; Bonn, Guenther K.; Huber, Lukas A.; Milas, Luka; Lukas, Peter

    2010-01-01

    Purpose: Radiation therapy cures malignant tumors of the head and neck region more effectively when it is combined with application of the anti-EGFR monoclonal antibody cetuximab. Despite the successes achieved, we still do not know how to select patients who will respond to this combination of anti-EGFR monoclonal antibody and radiation. This study was conducted to elucidate possible mechanisms which cause the combined treatment with cetuximab and irradiation to fail in some cases of squamous cell carcinomas. Methods and materials: Mice bearing FaDu and A431 squamous cell carcinoma xenograft tumors were treated with cetuximab (total dose 3 mg, intraperitoneally), irradiation (10 Gy) or their combination at the same doses. Treatment was applied when tumors reached 8 mm in size. To collect samples for further protein analysis (two-dimensional differential gel electrophoresis (2-D DIGE), mass spectrometry MALDI-TOF/TOF, Western blot analysis, and ELISA), mice from each group were sacrificed on the 8th day after the first injection of cetuximab. Other mice were subjected to tumor growth delay assay. Results: In FaDu xenografts, treatment with cetuximab alone was nearly as effective as cetuximab combined with ionizing radiation, whereas A431 tumors responded to the combined treatment with significantly enhanced delay in tumor growth. Tumors extracted from the untreated FaDu and A431 xenografts were analysed for protein expression, and 34 proteins that were differently expressed in the two tumor types were identified. The majority of these proteins are closely related to intratumoral angiogenesis, cell adhesion, motility, differentiation, epithelial-to-mesenchymal transition (EMT), c-myc signaling and DNA repair. Conclusions: The failure of cetuximab to enhance radiation response in FaDu xenografts was associated with the initiation of the program of EMT and with c-myc up-regulation in the carcinoma cells. For this reason, c-myc and EMT-related proteins (E

  8. Genetic dissimilarity between primary colorectal carcinomas and their lymph node metastases: ploidy, p53, bcl-2, and c-myc expression--a pilot study.

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    Zalata, Khaled Refaat; Elshal, Mohamed Farouk; Foda, Abd AlRahman Mohammad; Shoma, Ashraf

    2015-08-01

    The current paradigm of metastasis proposes that rare cells within primary tumors acquire metastatic capability via sequential mutations, suggesting that metastases are genetically dissimilar from their primary tumors. This study investigated the changes in the level of expression of a well-defined panel of cell proliferation, differentiation, and apoptosis markers between the primary colorectal cancer (CRC) and the corresponding synchronous lymph node (LN) metastasis from the same patients. DNA flow cytometry and immunostaining of p53, bcl-2, and c-myc were carried out on 36 cases of CRC radical resection specimens with their corresponding LN metastases. There was very low probability that the histological patterns of primary tumors and LN metastases are independent (p < 0.001). Metastatic tumors were significantly more diffusely positive for p53 than the primary tumors (p < 0.001). Conversely, primary tumors were significantly more diffusely positive for c-myc than metastatic tumors (p = 0.011). No significant difference was found between the LNs and the primary tumors in bcl-2 positivity (p = 0.538) and DNA aneuploidy (p = 0.35), with a tendency towards negative bcl-2 and less aneuploidy in LN metastases than primary tumors. In conclusion, LN metastatic colorectal carcinomas have a tendency of being less differentiated, with a higher incidence of diffuse p53 staining, lower incidence of bcl-2 staining, and less aneuploidy in comparison to their primary counterparts suggesting a more aggressive biological behavior, which could indicate the necessity for more aggressive adjuvant therapy.

  9. Soluble expression of recomb inant cMyc, Klf4, Oct4, and Sox2 proteins in bacteria and transduction into living cells

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    Guo-Dan Liu

    2017-04-01

    Full Text Available AIM: To develop a new method to produce recombinant reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, in soluble format with low cost for the generation of induced pluripotent stem cells (iPSCs. METHODS: A short polypeptide sequence derived from the HIV trans-activator of transcription protein (TAT and the nucleus localization signal (NLS polypeptide were fused to the N terminus of the reprogramming proteins and they were constructed into pCold-SUMO vector which can extremely improve the solubility of recombinant proteins. Then these vector plasmids were transformed into E. coli BL21 (DE3 Chaperone competent cells for amplification. The solubility of these recombinant proteins was determined by SDS-PAGE and Coomassie brilliant blue staining. The recombinant proteins were purified by Ni-NTA resin and identified by Western blot. The transduction of these proteins into HEK 293T cells were evaluated by immunofluorescence staining. RESULTS: These four reprogramming proteins could be produced in soluble format in pCold-SUMO expression vector system with the assistance of chaperone proteins in bacteria. The proteins were purified successfully with a purity of over 70% with a relative high transduction rate into 293 cells. CONCLUSION: The results in the present study indicate the four important reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, can be produced in soluble format in bacteria with low cost. Our new method thus might be expected to greatly contribute to the future study of iPSCs.

  10. Oridonin induces apoptosis and senescence in colorectal cancer cells by increasing histone hyperacetylation and regulation of p16, p21, p27 and c-myc

    International Nuclear Information System (INIS)

    Gao, Feng-Hou; Liu, Feng; Zhao, Ying-Zheng; Fang, Yong; Chen, Fang-Yuan; Wu, Ying-Li; Hu, Xiao-Hui; Li, Wei; Liu, Hua; Zhang, Yan-Jie; Guo, Zhu-Ying; Xu, Mang-Hua; Wang, Shi-Ting; Jiang, Bin

    2010-01-01

    Oridonin, a tetracycline diterpenoid compound, has the potential antitumor activities. Here, we evaluate the antitumor activity and action mechanisms of oridonin in colorectal cancer. Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit. Cell cycle distribution was determined by flow cytometry. Apoptosis was examined by analyzing subdiploid population and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Senescent cells were determined by senescence-associated β-galactosidase activity analysis. Semi-quantitative RT-PCR was used to examine the changes of mRNA of p16, p21, p27 and c-myc. The concomitant changes of protein expression were analyzed with Western blot. Expression of AcH3 and AcH4 were examined by immunofluorescence staining and Western blots. Effects of oridonin on colony formation of SW1116 were examined by Soft Agar assay. The in vivo efficacy of oridonin was detected using a xenograft colorectal cancer model in nude mice. Oridonin induced potent growth inhibition, cell cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg) for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice. With western blot and reverse transcription-PCR, we further showed that the antitumor activities of oridonin correlated with induction of histone (H3 and H4) hyperacetylation, activation of p21, p27 and p16, and suppression of c-myc expression. Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment

  11. Oridonin induces apoptosis and senescence in colorectal cancer cells by increasing histone hyperacetylation and regulation of p16, p21, p27 and c-myc

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    Zhao Ying-Zheng

    2010-11-01

    Full Text Available Abstract Background Oridonin, a tetracycline diterpenoid compound, has the potential antitumor activities. Here, we evaluate the antitumor activity and action mechanisms of oridonin in colorectal cancer. Methods Effects of oridonin on cell proliferation were determined by using a CCK-8 Kit. Cell cycle distribution was determined by flow cytometry. Apoptosis was examined by analyzing subdiploid population and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Senescent cells were determined by senescence-associated β-galactosidase activity analysis. Semi-quantitative RT-PCR was used to examine the changes of mRNA of p16, p21, p27 and c-myc. The concomitant changes of protein expression were analyzed with Western blot. Expression of AcH3 and AcH4 were examined by immunofluorescence staining and Western blots. Effects of oridonin on colony formation of SW1116 were examined by Soft Agar assay. The in vivo efficacy of oridonin was detected using a xenograft colorectal cancer model in nude mice. Results Oridonin induced potent growth inhibition, cell cycle arrest, apoptosis, senescence and colony-forming inhibition in three colorectal cancer cell lines in a dose-dependent manner in vitro. Daily i.p. injection of oridonin (6.25, 12.5 or 25 mg/kg for 28 days significantly inhibited the growth of SW1116 s.c. xenografts in BABL/C nude mice. With western blot and reverse transcription-PCR, we further showed that the antitumor activities of oridonin correlated with induction of histone (H3 and H4 hyperacetylation, activation of p21, p27 and p16, and suppression of c-myc expression. Conclusion Oridonin possesses potent in vitro and in vivo anti-colorectal cancer activities that correlated with induction of histone hyperacetylation and regulation of pathways critical for maintaining growth inhibition and cell cycle arrest. Therefore, oridonin may represent a novel therapeutic option in colorectal cancer treatment.

  12. PET/CT imaging of c-Myc transgenic mice identifies the genotoxic N-nitroso-diethylamine as carcinogen in a short-term cancer bioassay.

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    Katja Hueper

    Full Text Available BACKGROUND: More than 100,000 chemicals are in use but have not been tested for their safety. To overcome limitations in the cancer bioassay several alternative testing strategies are explored. The inability to monitor non-invasively onset and progression of disease limits, however, the value of current testing strategies. Here, we report the application of in vivo imaging to a c-Myc transgenic mouse model of liver cancer for the development of a short-term cancer bioassay. METHODOLOGY/PRINCIPAL FINDINGS: μCT and ¹⁸F-FDG μPET were used to detect and quantify tumor lesions after treatment with the genotoxic carcinogen NDEA, the tumor promoting agent BHT or the hepatotoxin paracetamol. Tumor growth was investigated between the ages of 4 to 8.5 months and contrast-enhanced μCT imaging detected liver lesions as well as metastatic spread with high sensitivity and accuracy as confirmed by histopathology. Significant differences in the onset of tumor growth, tumor load and glucose metabolism were observed when the NDEA treatment group was compared with any of the other treatment groups. NDEA treatment of c-Myc transgenic mice significantly accelerated tumor growth and caused metastatic spread of HCC in to lung but this treatment also induced primary lung cancer growth. In contrast, BHT and paracetamol did not promote hepatocarcinogenesis. CONCLUSIONS/SIGNIFICANCE: The present study evidences the accuracy of in vivo imaging in defining tumor growth, tumor load, lesion number and metastatic spread. Consequently, the application of in vivo imaging techniques to transgenic animal models may possibly enable short-term cancer bioassays to significantly improve hazard identification and follow-up examinations of different organs by non-invasive methods.

  13. P2-7: Encoding of Graded Changes in Validity of Spatial Priors in Human Visual Cortex

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    Yuko Hara

    2012-10-01

    Full Text Available If the spatial validity of prior information is varied systematically, does human behavioral performance improve in a graded fashion, and if so, does visual cortex represent the probability directly? Cortical activity was measured with fMRI while subjects performed a contrast-discrimination task in which the spatial validity of a prior cue for target location was systematically varied. Subjects viewed four sinusoidal gratings (randomized contrasts of 12.5, 25, and 50% shown in discrete visual quadrants presented twice. The contrast in one location (target was incremented in one of the two presentations. Subjects reported with a button press which presentation contained the greater contrast. The target grating was signaled in advance by a cue which varied in spatial validity; at trial onset, small lines pointed to four, two, or one of the possible target locations, thus indicating the target with 25, 50, or 100% probability. Behavioral performance was 2.1 and 3.3 times better in the 100% probability condition than the 50% and 25%, respectively (p < .001, ANOVA. Unlike behavioral performance, cortical activity in early visual areas showed the same increase in response amplitude for cued versus uncued stimuli for both 100% and 50% probability (V1-V4, V3A all p < .18, Student's t-test, 25% had no uncued condition. How could behavioral performance improve in a graded fashion if cortical activity showed the same effect for different probabilities? A model of efficient selection in which V1 responses were pooled according to their magnitude rather than as a simple average explained the observations (AIC difference = −15.

  14. Sphingosine kinase-1, S1P transporter spinster homolog 2 and S1P2 mRNA expressions are increased in liver with advanced fibrosis in human.

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    Sato, Masaya; Ikeda, Hitoshi; Uranbileg, Baasanjav; Kurano, Makoto; Saigusa, Daisuke; Aoki, Junken; Maki, Harufumi; Kudo, Hiroki; Hasegawa, Kiyoshi; Kokudo, Norihiro; Yatomi, Yutaka

    2016-08-26

    The role of sphingosine 1-phosphate (S1P) in liver fibrosis or inflammation was not fully examined in human. Controversy exists which S1P receptors, S1P1 and S1P3 vs S1P2, would be importantly involved in its mechanism. To clarify these matters, 80 patients who received liver resection for hepatocellular carcinoma and 9 patients for metastatic liver tumor were enrolled. S1P metabolism was analyzed in background, non-tumorous liver tissue. mRNA levels of sphingosine kinase 1 (SK1) but not SK2 were increased in livers with fibrosis stages 3-4 compared to those with 0-2 and to normal liver. However, S1P was not increased in advanced fibrotic liver, where mRNA levels of S1P transporter spinster homolog 2 (SPNS2) but not S1P-degrading enzymes were enhanced. Furthermore, mRNA levels of S1P2 but not S1P1 or S1P3 were increased in advanced fibrotic liver. These increased mRNA levels of SK1, SPNS2 and S1P2 in fibrotic liver were correlated with α-smooth muscle actin mRNA levels in liver, and with serum ALT levels. In conclusion, S1P may be actively generated, transported to outside the cells, and bind to its specific receptor in human liver to play a role in fibrosis or inflammation. Altered S1P metabolism in fibrotic liver may be their therapeutic target.

  15. Periplocin from Cortex periplocae inhibits cell growth and down-regulates survivin and c-myc expression in colon cancer in vitro and in vivo via beta-catenin/TCF signaling.

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    Zhao, Lianmei; Shan, Baoen; Du, Yanyan; Wang, Mingxia; Liu, Lihua; Ren, Feng-Zhi

    2010-08-01

    Cancer of the colon and rectum is the third most commonly diagnosed cancer and accounts for approximately 10% of all cancer-related deaths. Although surgical resection or radiotherapy are potentially curative for localized disease, advanced colon cancer is currently associated with poor prognosis. Therefore, the development of a new and effective chemotherapeutic agent is required to target critical pathways to induce responsiveness of colon cancer cells to death signals. Dysregulation of the beta-catenin/TCF pathway plays a central role in early activities of colorectal carcinogenesis. In this study, human colon cancer SW480 cells were used to investigate the effect of CPP (periplocin from Cortex periplocae) on the modulation of the beta-catenin/TCF signaling pathway. Our research results showed that CPP caused a dose- and time-dependent inhibition of cell growth as assessed by MTT assay and an induction in apoptosis as measured by flow cytometry and transmission electron microscopy. Furthermore, the CPP- treated cells were characterized by a decreased expression of beta-catenin protein in the total cell lysates and cytosolic and nuclear extracts. This expression alleviates the binding activity of T-cell factor (Tcf) complexes to its specific DNA-binding sites. Thus, the protein expression of the downstream elements survivin and c-myc was down-regulated. To determine the precise inhibitory mechanisms involved, further in-depth in vivo studies of CPP are warranted. In conclusion, our data suggest that CPP wields a multi-prong strategy to target the beta-catenin/Tcf signaling pathway, leading to the induction of apoptosis and inhibition of growth of colon cancer cells in vitro and in vivo. Therefore, CPP may become a potential agent against colon cancer.

  16. Inhibition of bromodomain and extra-terminal (BET) proteins increases NKG2D ligand MICA expression and sensitivity to NK cell-mediated cytotoxicity in multiple myeloma cells: role of cMYC-IRF4-miR-125b interplay.

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    Abruzzese, Maria Pia; Bilotta, Maria Teresa; Fionda, Cinzia; Zingoni, Alessandra; Soriani, Alessandra; Vulpis, Elisabetta; Borrelli, Cristiana; Zitti, Beatrice; Petrucci, Maria Teresa; Ricciardi, Maria Rosaria; Molfetta, Rosa; Paolini, Rossella; Santoni, Angela; Cippitelli, Marco

    2016-12-01

    Anti-cancer immune responses may contribute to the control of tumors after conventional chemotherapy, and different observations have indicated that chemotherapeutic agents can induce immune responses resulting in cancer cell death and immune-stimulatory side effects. Increasing experimental and clinical evidence highlight the importance of natural killer (NK) cells in immune responses toward multiple myeloma (MM), and combination therapies able to enhance the activity of NK cells against MM are showing promise in treating this hematologic cancer. The epigenetic readers of acetylated histones bromodomain and extra-terminal (BET) proteins are critical regulators of gene expression. In cancer, they can upregulate transcription of key oncogenes such as cMYC, IRF4, and BCL-2. In addition, the activity of these proteins can regulate the expression of osteoclastogenic cytokines during cancer progression. Here, we investigated the effect of BET bromodomain protein inhibition, on the expression of NK cell-activating ligands in MM cells. Five MM cell lines [SKO-007(J3), U266, RPMI-8226, ARP-1, JJN3] and CD138 + MM cells isolated from MM patients were used to investigate the activity of BET bromodomain inhibitors (BETi) (JQ1 and I-BET151) and of the selective BRD4-degrader proteolysis targeting chimera (PROTAC) (ARV-825), on the expression and function of several NK cell-activating ligands (NKG2DLs and DNAM-1Ls), using flow cytometry, real-time PCR, transient transfections, and degranulation assays. Our results indicate that inhibition of BET proteins via small molecule inhibitors or their degradation via a hetero-bifunctional PROTAC probe can enhance the expression of MICA, a ligand of the NKG2D receptor, in human MM cell lines and primary malignant plasma cells, rendering myeloma cells more efficient to activate NK cell degranulation. Noteworthy, similar results were obtained using selective CBP/EP300 bromodomain inhibition. Mechanistically, we found that BETi

  17. Thermo-Responsive Complexes of c-Myc Antisense Oligonucleotide with Block Copolymer of Poly(OEGMA) and Quaternized Poly(4-Vinylpyridine).

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    Topuzogullari, Murat; Elalmis, Yeliz Basaran; Isoglu, Sevil Dincer

    2017-04-01

    Solution behavior of thermo-responsive polymers and their complexes with biological macromolecules may be affected by environmental conditions, such as the concentration of macromolecular components, pH, ion concentration, etc. Therefore, a thermo-responsive polymer and its complexes should be characterized in detail to observe their responses against possible environments under physiological conditions before biological applications. To briefly indicate this important issue, thermo-responsive block copolymer of quaternized poly(4-vinylpyridine) and poly(oligoethyleneglycol methyl ether methacrylate) as a potential nonviral vector has been synthesized. Polyelectrolyte complexes of this copolymer with the antisense oligonucleotide of c-Myc oncogene are also thermo-responsive but, have lower LCST (lower critical solution temperature) values compared to individual copolymer. LCST values of complexes decrease with molar ratio of macromolecular components and presence of salt. Dilution of solutions also affects solution behavior of complexes and causes a significant decrease in size and an increase in LCST, which indicates possible effects of severe dilutions in the blood stream. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Melatonin promotes circadian rhythm-induced proliferation through Clock/histone deacetylase 3/c-Myc interaction in mouse adipose tissue.

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    Liu, Zhenjiang; Gan, Lu; Luo, Dan; Sun, Chao

    2017-05-01

    Melatonin is synthesized in the pineal gland and controls circadian rhythm of peripheral adipose tissue, resulting in changes in body weight. Although core regulatory components of clock rhythmicity have been defined, insight into the mechanisms of circadian rhythm-mediated proliferation in adipose tissue is still limited. Here, we showed that melatonin (20 mg/kg/d) promoted circadian and proliferation processes in white adipose tissue. The circadian amplitudes of brain and muscle aryl hydrocarbon receptor nuclear translocator-like 1 (Bmal1, Pcircadian locomotor output cycles kaput (Clock, Pcircadian disruption and promoted adipocyte proliferation in chronic jet-lagged mice and obese mice. Thus, our study found that melatonin promoted adipocyte proliferation by forming a Clock/HDAC3/c-Myc complex and subsequently driving the circadian amplitudes of proliferation genes. Our data reveal a novel mechanism that links circadian rhythm to cell proliferation in adipose tissue. These findings also identify a new potential means for melatonin to prevent and treat sleep deprivation-caused obesity. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Promoter trans-activation of protooncogenes c-fos and c-myc, but not c-Ha-ras, by products of adenovirus early region 1A

    International Nuclear Information System (INIS)

    Sassone-Corsi, P.; Borrelli, E.

    1987-01-01

    The E1A (early region 1A) oncogene products of adenovirus type 2 trans-activate the other early viral transcription units, as well as some cellular promoters. Using a short-term cotransfection assay in murine NIH 3T3 fibroblasts, we show that c-fos and c-myc promoter activities are stimulated by the E1A proteins, whereas c-Ha-ras transcription is not affected. The product of E1A 13S mRNA is responsible for the trans-activation, whereas the 12S mRNA product has no effect. Analysis of the c-fos promoter sequences required for the E1A stimulation shows that responsive sequences are located between positions -402 and -240 upstream of the transcription initiation site. This same region also contains the c-fos serum-responsive element. Furthermore, transcription of the endogenous c-fos gene in HeLa cells is increased after E1A transfection

  20. [Survival of patients with primary central nervous system diffuse large B-cell lymphoma: impact of gene aberrations and protein overexpression of bcl-2 and C-MYC, and selection of chemotherapy regimens].

    Science.gov (United States)

    Yin, W J; Zhu, X; Yang, H Y; Sun, W Y; Wu, M J

    2018-01-08

    Objective: To investigate the impact of clinicopathological features, gene rearrangements and protein expression of bcl-6, bcl-2, C-MYC and chemotherapy regime on the prognosis of patients with primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL). Methods: Thirty-three cases of PCNS-DLBCL diagnosed from January 2006 to December 2016 at Zhejiang Cancer Hospital were collected. The expression of CD10, bcl-6, bcl-2, MUM1 and MYC were detected by immunohistochemical staining (IHC). The presence of EB virus was detected by in situ hybridization(EBER). Copy number variation (ICN) and translocation status of bcl-6, bcl-2 and C-MYC genes were detected by fluorescence in situ hybridization (FISH). The relationship between the above indexes and the prognosis was analyzed by univariate, bivariate survival analysis and multiple Cox hazard regression analysis. Results: The study included 33 patients of PCNS-DLBCL, without evidence of primary or secondary immunodeficient disease. Male to female ratio was 1.36∶1.00, and the average age was 56 years. Twenty cases had single lesion while 13 had multiple lesions. Deep brain involvement was seen in 12 cases. All patients underwent partial or total tumor resection. Five patients received whole brain post-surgery radiotherapy, nine patients received high-dose methotrexate (HD-MTX) based chemotherapy, and 12 patients received whole-brain radiotherapy combined with HD-MTX based chemotherapy. Severn patients received no further treatment and rituximab was used in 8 patients. According to the Hans model, 27 cases were classified as non-GCB subtypes (81.8%). Bcl-2 was positive in 25 cases (75.8%, 25/33) and highly expressed in 8 (24.2%). MYC was positive in 12 cases (36.4%) and double expression of bcl-2 and MYC was seen in 6 cases. EBER positive rate was 10.0%(3/30), all of which had multiple lesions. Two bcl-6 gene translocations and 3 amplifications were found in 28 patients. Two translocations, 3 ICN or with both

  1. Primary central nervous system diffuse large B-cell lymphoma shows an activated B-cell-like phenotype with co-expression of C-MYC, BCL-2, and BCL-6.

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    Li, Xiaomei; Huang, Ying; Bi, Chengfeng; Yuan, Ji; He, Hong; Zhang, Hong; Yu, QiuBo; Fu, Kai; Li, Dan

    2017-06-01

    Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, whose main prognostic factor is closely related to germinal center B-cell-like subtype (GCB- DLBCL) or activated B-cell-like type (non-GCB-DLBCL). The most common type of primary central nervous system lymphoma is diffuse large B-cell type with poor prognosis and the reason is unclear. This study aims to stratify primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) according to the cell-of-origin (COO) and to investigate the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53, further to elucidate the reason why primary central nervous system diffuse large B-cell lymphoma possesses a poor clinical outcome as well. Nineteen cases of primary central nervous system DLBCL were stratified according to immunostaining algorithms of Hans, Choi and Meyer (Tally) and we investigated the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53. The Epstein-Barr virus and Borna disease virus infection were also detected. Among nineteen cases, most (15-17 cases) were assigned to the activated B-cell-like subtype, highly expression of C-MYC (15 cases, 78.9%), BCL-2 (10 cases, 52.6%), BCL-6 (15 cases, 78.9%). Unfortunately, two cases were positive for PD-L1 while PD-L2 was not expressed in any case. Two cases infected with BDV but no one infected with EBV. In conclusion, most primary central nervous system DLBCLs show an activated B-cell-like subtype characteristic and have multiple expressions of C-MYC, BCL-2, BCL-6 protein, these features might be significant factor to predict the outcome and guide treatment of PCNS-DLBCLs. Copyright © 2017 Elsevier GmbH. All rights reserved.

  2. cAMP-Dependent Protein Kinase A (PKA)-Mediated c-Myc Degradation Is Dependent on the Relative Proportion of PKA-I and PKA-II Isozymes.

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    Liu, Qingyuan; Nguyen, Eric; Døskeland, Stein; Ségal-Bendirdjian, Évelyne

    2015-09-01

    The transcription factor c-Myc regulates numerous target genes that are important for multiple cellular processes such as cell growth and differentiation. It is commonly deregulated in leukemia. Acute promyelocytic leukemia (APL) is characterized by a blockade of granulocytic differentiation at the promyelocyte stage. Despite the great success of all-trans retinoic acid (ATRA)-based therapy, which results in a clinical remission by inducing promyelocyte maturation, a significant number of patients relapse due to the development of ATRA resistance. A significant role has been ascribed to the cAMP/cAMP-dependent protein kinase A (PKA) signaling pathway in retinoid treatment since PKA activation is able to restore differentiation in some ATRA-resistant cells and eradicate leukemia-initiating cells in vivo. In this study, using NB4 APL cell variants resistant to ATRA-induced differentiation, we reveal distinct functional roles of the two PKA isozymes, PKA type I (PKA-I) and PKA-type II (PKA-II), on the steady-state level of c-Myc protein, providing a likely mechanism by which cAMP-elevating agents can restore differentiation in ATRA maturation-resistant APL cells. Therefore, both the inhibition of c-Myc activity and the PKA-I/PKA-II ratio should be taken into account if cAMP-based therapy is considered in the clinical management of APL. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  3. The use of computerized video time lapse to study cell death in rat embryo cells transfected with c-ha-ras or c-myc

    International Nuclear Information System (INIS)

    Forrester, H.B.; Vidair, C.A.; Dewey, W.C.; Ling, C.C.

    1998-01-01

    Full text: Individual rat embryo fibroblasts that had been transfected with the c-myc (REC:myc) or c-Ha ras (REC:ras) oncogene were followed after irradiation using a computer video time lapse (CVTL) system in order to quantify the lethal events that resulted in loss of clonogenic survival after irradiation. By followed the cells for 2 to 3 generations before irradiation we were able to determine where they were in the cell cycle at the time of irradiation for cell cycle analysis. After irradiation, the individual cells and their progeny were followed in multiple fields for 5-6 days Then, pedigrees for individual irradiated cells were determined by noting the times of divisions fusions, and cell death. After X-irradiation, the clonogenic survival values for these two cell lines are similar. However, by using computerized video time lapse (CVTL) to follow individual cells we found that the loss of clonogenic survival was due to two different processes, cell death and a senescent-like process. The loss of clonogenic survival of x-irradiated (9.5 and 4 Gy) REC:myc cells was attributed almost entirely to the cells dying by apoptosis (∼99 and 90%). In contrast, approximately 60% of the x-irradiated (9.5 Gy) non-clonogenic REC:ras cells died by apoptosis (with a very small amount of necrosis), and the other 40% underwent a senescent-type process in which some of the cells and their progeny stopped dividing but remained as viable cells throughout 140 hours of observation. Both processes usually occurred after the cells had divided and continued to occur in the cells' progeny for up to five divisions after irradiation. The mode of cell death in the progeny of a non-clonogenic cell can be determined only by using CVTL and can not be determined by conventional clonogenic survival experiments. Also, only by following the individual cells and their progeny can the true amount of apoptosis be determined. The cumulative percentage of apoptosis scored in whole populations

  4. Pyrid-2-yl and 2-CyanoPhenyl fused heterocyclic compounds as human P2X3 inhibitors: a combined approach based on homology modelling, docking and QSAR analysis.

    Science.gov (United States)

    Janardhan, Sridhara; Seth, Subhendu; Viswanadhan, Vellarkad N

    2014-02-01

    P2X receptors are hetero-oligomeric proteins that function as membrane ion channels and are gated by extracellular ATP. The hP2X[Formula: see text] subunit is a constituent of the channels on a subset of sensory neurons involved in pain signaling, where ATP released by damaged and inflamed tissue can initiate action potentials. Hence, the inhibition of ATP-activated P2X3 receptor is an exciting approach for the treatment of inflammatory and neuropathic pain. Recently, the crystal structures of zebrafish P2X4 (zP2X4) were obtained in closed, apo state (PDB ID: 3I5D) and ATP-bound, open state (PDB ID: 4DW1). These structures were used to develop a homology model of human P2X3 (hP2X3 in order to identify through docking studies, the binding modes of known P2X3 inhibitors and their key active site interactions, along with a pharmacophore-based 3D-QSAR model for a series of 136 Pyrid-2-yl and 2-CyanoPhenyl fused heterocyclic compounds. These 3D-QSAR models have been developed with different combinations of training and test set divisions obtained by random separation, Jarvis-Patrick clustering, K-means clustering and sphere exclusion methods. The best predictive 3D-QSAR model resulted in training set R2 of 0.75, internal test set Q2 of 0.74, Pearson-R value of 0.87 and root mean square error of 0.37. The information generated by the pharmacophore model and docking analyses using the homology model provides valuable clues to design novel potent hP2X3 inhibitors.

  5. Investigation of miRNA Biology by Bioinformatic Tools and Impact of miRNAs in Colorectal Cancer: Regulatory Relationship of c-Myc and p53 with miRNAs

    Directory of Open Access Journals (Sweden)

    Yaguang Xi

    2007-01-01

    Full Text Available MicroRNAs (miRNAs are a class of small non-coding RNAs that mediate gene expression at the posttranscriptional and translational levels and have been demonstrated to be involved in diverse biological functions. Mounting evidence in recent years has shown that miRNAs play key roles in tumorigenesis due to abnormal expression of and mutations in miRNAs. High throughput miRNA expression profiling of several major tumor types has identified miRNAs associated with clinical diagnosis and prognosis of cancer treatment. Previously our group has discovered a novel regulatory relationship between tumor suppressor gene p53 with miRNAs expression and a number of miRNA promoters contain putative p53 binding sites. In addition, others have reported that c-myc can mediate a large number of miRNAs expression. In this review, we will emphasize algorithms to identify mRNA targets of miRNAs and the roles of miRNAs in colorectal cancer. In particular, we will discuss a novel regulatory relationship of miRNAs with tumor suppressor p53 and c-myc. miRNAs are becoming promising novel targets and biomarkers for future cancer therapeutic development and clinical molecular diagnosis.

  6. Nucleotide sequence of the human N-myc gene

    International Nuclear Information System (INIS)

    Stanton, L.W.; Schwab, M.; Bishop, J.M.

    1986-01-01

    Human neuroblastomas frequently display amplification and augmented expression of a gene known as N-myc because of its similarity to the protooncogene c-myc. It has therefore been proposed that N-myc is itself a protooncogene, and subsequent tests have shown that N-myc and c-myc have similar biological activities in cell culture. The authors have now detailed the kinship between N-myc and c-myc by determining the nucleotide sequence of human N-myc and deducing the amino acid sequence of the protein encoded by the gene. The topography of N-myc is strikingly similar to that of c-myc: both genes contain three exons of similar lengths; the coding elements of both genes are located in the second and third exons; and both genes have unusually long 5' untranslated regions in their mRNAs, with features that raise the possibility that expression of the genes may be subject to similar controls of translation. The resemblance between the proteins encoded by N-myc and c-myc sustains previous suspicions that the genes encode related functions

  7. The influence of the cell cycle, differentiation and irradiation on the nuclear location of the abl, brc and c-myc genes in human leukemic cells

    Czech Academy of Sciences Publication Activity Database

    Bártová, Eva; Kozubek, Stanislav; Kozubek, Michal; Jirsová, Pavla; Lukášová, Emilie; Skalníková, M.; Buchníčková, Katarína

    2000-01-01

    Roč. 24, - (2000), s. 233-241 ISSN 0145-2126 R&D Projects: GA ČR GA202/97/0874; GA ČR GA202/98/P253; GA MZd NM15 Institutional research plan: CEZ:A17/98:Z5-004-9-ii Subject RIV: BO - Biophysics Impact factor: 1.502, year: 2000

  8. The Phosphoinositide 3-Kinase p110α Isoform Regulates Leukemia Inhibitory Factor Receptor Expression via c-Myc and miR-125b to Promote Cell Proliferation in Medulloblastoma.

    Directory of Open Access Journals (Sweden)

    Fabiana Salm

    Full Text Available Medulloblastoma (MB is the most common malignant brain tumor in childhood and represents the main cause of cancer-related death in this age group. The phosphoinositide 3-kinase (PI3K pathway has been shown to play an important role in the regulation of medulloblastoma cell survival and proliferation, but the molecular mechanisms and downstream effectors underlying PI3K signaling still remain elusive. The impact of RNA interference (RNAi-mediated silencing of PI3K isoforms p110α and p110δ on global gene expression was investigated by DNA microarray analysis in medulloblastoma cell lines. A subset of genes with selectively altered expression upon p110α silencing in comparison to silencing of the closely related p110δ isoform was revealed. Among these genes, the leukemia inhibitory factor receptor α (LIFR α was validated as a novel p110α target in medulloblastoma. A network involving c-Myc and miR-125b was shown to be involved in the control of LIFRα expression downstream of p110α. Targeting the LIFRα by RNAi, or by using neutralizing reagents impaired medulloblastoma cell proliferation in vitro and induced a tumor volume reduction in vivo. An analysis of primary tumors revealed that LIFRα and p110α expression were elevated in the sonic hedgehog (SHH subgroup of medulloblastoma, indicating its clinical relevance. Together, these data reveal a novel molecular signaling network, in which PI3K isoform p110α controls the expression of LIFRα via c-Myc and miR-125b to promote MB cell proliferation.

  9. Effect of stent absorbed c-myc antisense oligodeoxynucleotide on smooth muscle cells apoptosis in rabbit carotid artery%反义c-myc涂层支架对兔颈动脉细胞凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    张新霞; 崔长琮; 李江; 孟猛; 徐仓宝; 赵一岭

    2001-01-01

    目的:探讨铂-铱合金明胶蛋白涂层支架局部导入c-myc反义寡核苷酸(ASODN)对兔颈动脉细胞凋亡的影响,寻求防治支架内再狭窄的途径.方法:将携带c-myc ASODN的国产铂铱合金明胶蛋白涂层支架置入兔颈动脉(给药组,n=16),在术后7、14、30、90 d处死动物行苏木精-伊红和Weigert染色,图像分析测量新生内膜厚度和面积,c-myc蛋白免疫组化染色,采用末端脱氧核苷酸酶介导的dUTP缺口末端标记法检测细胞凋亡,并与对照组(n=16)进行对比分析.结果:两组支架术后7、1 4 d均未观察到平滑肌细胞凋亡,术后30 d在新生内膜中观察到明显的细胞凋亡,90 d时显著高于30 d;同时给药组平滑肌细胞的凋亡显著高于对照组.结论:c myc ASODN可诱导支架置入后平滑肌细胞凋亡,可用于防治再狭窄.

  10. The FDA approved PI3K inhibitor GDC-0941 enhances in vitro the anti-neoplastic efficacy of Axitinib against c-myc-amplified high-risk medulloblastoma.

    Science.gov (United States)

    Ehrhardt, Michael; Craveiro, Rogerio B; Velz, Julia; Olschewski, Martin; Casati, Anna; Schönberger, Stefan; Pietsch, Torsten; Dilloo, Dagmar

    2018-04-01

    Aberrant receptor kinase signalling and tumour neovascularization are hallmarks of medulloblastoma development and are both considered valuable therapeutic targets. In addition to VEGFR1/2, expression of PDGFR α/β in particular has been documented as characteristic of metastatic disease correlating with poor prognosis. Therefore, we have been suggested that the clinically approved multi-kinase angiogenesis inhibitor Axitinib, which specifically targets these kinases, might constitute a promising option for medulloblastoma treatment. Indeed, our results delineate anti-neoplastic activity of Axitinib in medulloblastoma cell lines modelling the most aggressive c-myc-amplified Non-WNT/Non-SHH and SHH-TP53-mutated tumours. Exposure of medulloblastoma cell lines to Axitinib results in marked inhibition of proliferation and profound induction of cell death. The differential efficacy of Axitinib is in line with target expression of medulloblastoma cells identifying VEGFR 1/2, PDGFR α/β and c-kit as potential markers for drug application. The high specificity of Axitinib and the consequential low impact on the haematopoietic and immune system render this drug ideal multi-modal treatment approaches. In this context, we demonstrate that the clinically available PI3K inhibitor GDC-0941 enhances the anti-neoplastic efficacy of Axitinib against c-myc-amplified medulloblastoma. Our findings provide a rational to further evaluate Axitinib alone and in combination with other therapeutic agents for the treatment of most aggressive medulloblastoma subtypes. © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  11. The p2 domain of human immunodeficiency virus type 1 Gag regulates sequential proteolytic processing and is required to produce fully infectious virions.

    OpenAIRE

    Pettit, S C; Moody, M D; Wehbie, R S; Kaplan, A H; Nantermet, P V; Klein, C A; Swanstrom, R

    1994-01-01

    The proteolytic processing sites of the human immunodeficiency virus type 1 (HIV-1) Gag precursor are cleaved in a sequential manner by the viral protease. We investigated the factors that regulate sequential processing. When full-length Gag protein was digested with recombinant HIV-1 protease in vitro, four of the five major processing sites in Gag were cleaved at rates that differ by as much as 400-fold. Three of these four processing sites were cleaved independently of the others. The CA/p...

  12. Bone phenotypes of P2 receptor knockout mice

    DEFF Research Database (Denmark)

    Orriss, Isabel; Syberg, Susanne; Wang, Ning

    2011-01-01

    The action of extracellular nucleotides is mediated by ionotropic P2X receptors and G-protein coupled P2Y receptors. The human genome contains 7 P2X and 8 P2Y receptor genes. Knockout mice strains are available for most of them. As their phenotypic analysis is progressing, bone abnormalities have...... been observed in an impressive number of these mice: distinct abnormalities in P2X7-/- mice, depending on the gene targeting construct and the genetic background, decreased bone mass in P2Y1-/- mice, increased bone mass in P2Y2-/- mice, decreased bone resorption in P2Y6-/- mice, decreased bone...... formation and bone resorption in P2Y13-/- mice. These findings demonstrate the unexpected importance of extracellular nucleotide signalling in the regulation of bone metabolism via multiple P2 receptors and distinct mechanisms involving both osteoblasts and osteoclasts....

  13. Anonymity in P2P Systems

    Science.gov (United States)

    Manzanares-Lopez, Pilar; Muñoz-Gea, Juan Pedro; Malgosa-Sanahuja, Josemaria; Sanchez-Aarnoutse, Juan Carlos

    In the last years, the use of peer-to-peer (P2P) applications to share and exchange knowledge among people around the world has experienced an exponential growth. Therefore, it is understandable that, like in any successful communication mechanism used by a lot of humans being, the anonymity can be a desirable characteristic in this scenario. Anonymity in P2P networks can be obtained by means of different methods, although the most significant ones are broadcast protocols, dining-cryptographer (DC) nets and multiple-hop paths. Each of these methods can be tunable in order to build a real anonymity P2P application. In addition, there is a mathematical tool called entropy that can be used in some scenarios to quantify anonymity in communication networks. In some cases, it can be calculated analytically but in others it is necessary to use simulation to obtain the network entropy.

  14. PPADS and suramin as antagonists at cloned P2Y- and P2U-purinoceptors.

    Science.gov (United States)

    Charlton, S J; Brown, C A; Weisman, G A; Turner, J T; Erb, L; Boarder, M R

    1996-06-01

    1. The effect of suramin and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) on the stimulation of phospholipase C in 1321N1 cells transfected with the human P2U-purinoceptor (h-P2U-1321N1 cells) or with the turkey P2Y-purinoceptor (t-P2Y-1321N1 cells) was investigated. 2-Methylthioadenosine triphosphate (2MeSATP) was used as the agonist at t-P2Y-1321N1 cells and uridine triphosphate (UTP) at h-P2U-1321N1 cells. 2. Suramin caused a parallel shift to the right of the concentration-response curves for 2MeSATP in the t-P2Y-1321N1 cells, yielding a Schild plot with a slope of 1.16 +/- 0.08 and a pA2 value of 5.77 +/- 0.11. 3. Suramin also caused a shift to the right of concentration-response curves for UTP in the h-P2U-1321N1 cells, and on Schild plots gave a slope different from unity (1.57 +/- 0.19) and an apparent pA2 value of 4.32 +/- 0.13. Suramin was therefore a less potent antagonist at the P2U-purinoceptor than the P2Y-purinoceptor. 4. In the presence of the ectonucleotidase inhibitor, ARL 67156 (6-N,N-diethyl-beta,gamma-dibromomethylene-D-ATP) there was no significant difference in the EC50 or shapes of curves with either cell type, and no difference in pA2 values for suramin. 5. PPADS caused an increase in the EC50 for 2MeSATP in the t-P2Y-1321N1 cells. The Schild plot had a slope different from unity (0.55 +/- 0.15) and an X-intercept corresponding to an apparent pA2 of 5.98 +/- 0.65. 6. PPADS up to 30 microM had no effect on the concentration-response curve for UTP with the h-P2U-1321N1 cells. 7. In conclusion, suramin and PPADS show clear differences in their action at the 2 receptor types, in each case being substantially more effective as an antagonist at the P2Y-purinoceptor than at the P2U-purinoceptor. Ectonucleotidase breakdown had little influence on the nature of the responses at the two receptor types, or in their differential sensitivity to suramin.

  15. Medicinal chemistry of adenosine, P2Y and P2X receptors.

    Science.gov (United States)

    Jacobson, Kenneth A; Müller, Christa E

    2016-05-01

    Pharmacological tool compounds are now available to define action at the adenosine (ARs), P2Y and P2X receptors. We present a selection of the most commonly used agents to study purines in the nervous system. Some of these compounds, including A1 and A3 AR agonists, P2Y1R and P2Y12R antagonists, and P2X3, P2X4 and P2X7 antagonists, are potentially of clinical use in treatment of disorders of the nervous system, such as chronic pain, neurodegeneration and brain injury. Agonists of the A2AAR and P2Y2R are already used clinically, P2Y12R antagonists are widely used antithrombotics and an antagonist of the A2AAR is approved in Japan for treating Parkinson's disease. The selectivity defined for some of the previously introduced compounds has been revised with updated pharmacological characterization, for example, various AR agonists and antagonists were deemed A1AR or A3AR selective based on human data, but species differences indicated a reduction in selectivity ratios in other species. Also, many of the P2R ligands still lack bioavailability due to charged groups or hydrolytic (either enzymatic or chemical) instability. X-ray crystallographic structures of AR and P2YRs have shifted the mode of ligand discovery to structure-based approaches rather than previous empirical approaches. The X-ray structures can be utilized either for in silico screening of chemically diverse libraries for the discovery of novel ligands or for enhancement of the properties of known ligands by chemical modification. Although X-ray structures of the zebrafish P2X4R have been reported, there is scant structural information about ligand recognition in these trimeric ion channels. In summary, there are definitive, selective agonists and antagonists for all of the ARs and some of the P2YRs; while the pharmacochemistry of P2XRs is still in nascent stages. The therapeutic potential of selectively modulating these receptors is continuing to gain interest in such fields as cancer, inflammation, pain

  16. Complex Biological Systems Analysis of Cell Cycling Models in Carcinogenesis: I. The essential roles of modifications in the c-Myc, TP53/p53, p27 and hTERT modules in Cancer Initiation and Progression

    CERN Document Server

    Prisecaru, V I

    2004-01-01

    A new approach to the integration of results from a modular, complex biological systems analysis of nonlinear dynamics in cell cycling network transformations that are leading to carcinogenesis is proposed. Carcinogenesis is a complex process that involves dynamically inter-connected biomolecules in the intercellular, membrane, cytosolic, nuclear and nucleolar compartments that form numerous inter-related pathways referred to as networks. One such network module contains the cell cyclins whose functions are essential to cell cycling and division. Cyclins are proteins that also link to several critical pro-apoptotic and other cell cycling/division components, such as: c-Myc, p27, the tumor suppressor gene TP53 and its product-- the p53 protein with key roles in controlling DNA repair, inducing apoptosis and activating p21 (which can depress cell cyclins if activated), mdm2(with its biosynthesis activated by p53 and also, in its turn, inhibiting p53), p21, the Thomsen-Friedenreich antigen(T- antigen),Rb,Bax, Ba...

  17. Maternal and Infant Factors Associated With Failure to Thrive in Children With Vertically Transmitted Human Immunodeficiency Virus-1 Infection: The Prospective, P2C2 Human Immunodeficiency Virus Multicenter Study

    Science.gov (United States)

    Miller, Tracie L.; Easley, Kirk A.; Zhang, Weihong; Orav, E. John; Bier, Dennis M.; Luder, Elisabeth; Ting, Andrew; Shearer, William T.; Vargas, Jorge Humberto; Lipshultz, Steven E.

    2015-01-01

    Objective Many children with human immunodeficiency virus-1 (HIV-1) have chronic problems with growth and nutrition, yet limited information is available to identify infected children at high risk for growth abnormalities. Using data from the prospective, multicenter P2C2 HIV study, we evaluated the relationships between maternal and infant clinical and laboratory factors and impaired growth in this cohort. Methods Children of HIV-1–infected women were enrolled prenatally or within the first 28 days of life. Failure to thrive (FTT) was defined as an age- and sex-adjusted weight z score ≤−2.0 SD. Maternal baseline covariates included age, race, illicit drug use, zidovudine use, CD4+ T-cell count, and smoking. Infant baseline predictors included sex, race, CD4+ T-cell count, Centers for Disease Control stage, HIV-1 RNA, antiretroviral therapy, pneumonia, heart rate, cytomegalovirus, and Epstein–Barr virus infection status. Results The study cohort included 92 HIV-1–infected and 439 uninfected children. Infected children had a lower mean gestational age, but birth weights, lengths, and head circumferences in the 2 groups were similar. Mothers of growth-delayed infants were more likely to have smoked tobacco and used illicit drugs during pregnancy. In repeated-measures analyses of weight and length or height z scores, the means of the HIV-1–infected group were significantly lower at 6 months of age (P < .001) and remained lower throughout the first 5 years of life. In a multivariable Cox regression analysis, FTT was associated with a history of pneumonia (relative risk [RR] = 8.78; 95% confidence interval [CI]: 3.59–21.44), maternal use of cocaine, crack, or heroin during pregnancy (RR = 3.17; 95% CI: 1.51–6.66), infant CD4+ T-cell count z score (RR = 2.13 per 1 SD decrease; 95% CI: 1.25–3.57), and any antiretroviral therapy by 3 months of age (RR = 2.77; 95% CI: 1.16–6.65). After adjustment for pneumonia and antiretroviral therapy, HIV-1 RNA load

  18. Towards P2P XML Database Technology

    NARCIS (Netherlands)

    Y. Zhang (Ying)

    2007-01-01

    textabstractTo ease the development of data-intensive P2P applications, we envision a P2P XML Database Management System (P2P XDBMS) that acts as a database middle-ware, providing a uniform database abstraction on top of a dynamic set of distributed data sources. In this PhD work, we research which

  19. Generation of human iPSC line GRX-MCiPS4F-A2 from adult peripheral blood mononuclear cells (PBMCs with Spanish genetic background

    Directory of Open Access Journals (Sweden)

    Sonia Cabrera

    2015-09-01

    Full Text Available We have generated iPSCs from peripheral blood mononuclear cells (PBMCs of a healthy man using heat sensitive and non-integrative Sendai virus containing Sox2, Oct3/4, c-Myc and Klf4. Human GRX-MCiPS4F-A2 cell line was established and characterized through this study.

  20. The role of P2X receptors in bone biology

    DEFF Research Database (Denmark)

    Jørgensen, N R; Syberg, S; Ellegaard, M

    2015-01-01

    receptors regulate bone metabolism and especially for the P2X7 receptor an impressive amount of evidence has now documented its expression in osteoblasts, osteoclasts, and osteocytes as well as important functional roles in proliferation, differentiation, and function of the cells of bone. Key evidence has...... come from studies on murine knockout models and from pharmacologic studies on cells and animals. More recently, the role of P2X receptors in human bone diseases has been documented. Loss-of-functions polymorphisms in the P2X7 receptorare associated with bone loss and increased fracture risk. Very...

  1. Fabrication and evaluation of osteoblastic differentiation of human mesenchymal stem cells on novel CaO-SiO2-P2O5-B2O3 glass-ceramics.

    Science.gov (United States)

    Lee, Jae Hyup; Seo, Jun-Hyuk; Lee, Kyung Mee; Ryu, Hyun-Seung; Baek, Hae-Ri

    2013-07-01

    Apatite-wollastonite glass-ceramics have high mechanical strength, and CaO-SiO2 -B2 O3 glass-ceramics showed excellent bioactivity and high biodegradability. A new type of CaO-SiO2 -P2 O5 -B2 O3 system of bioactive glass-ceramics (BGS-7) was fabricated, and the effect and usefulness was evaluated via bioactivity using simulated body fluid and human mesenchymal stem cells (hMSCs). The purpose of this study was to compare BGS-7 and hydroxyapatite (HA) using hMSCs in order to evaluate the bioactivity of BGS-7 and its possibility as a bone graft extender. Alkaline phosphatase (ALP) staining, ALP activity, cell proliferation 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay, Alizarin Red-S (AR-S) staining, calcium levels, the mRNA expression of ALP, osteocalcin, osteopontin, and runt-related transcription factor 2 (runx-2) using reverse-transcription polymerase chain reaction (RT-PCR) and the protein expression of osteocalcin and runx-2 using Western blot were measured by transplanting hMSC onto a tissue culture plate, HA, and BGS-7. The ALP staining and AR-S staining of BGS-7 was greater than that of HA and control. The ALP value of BGS-7 was significantly higher than that of HA and control. The MTS results showed that BGS-7 had a higher value than the groups transplanted onto HA and control on day 15. The calcium level was higher than the control in both HA and BGS-7, and was especially high in BGS-7. There were more mineral products on BGS-7 than on the HA when analyzed by scanning electron microscopy. The mRNA expression of ALP, osteopontin, osteocalcin, and runx-2 were higher on BGS-7 than on HA and the control when analyzed by RT-PCR. The relative gene expression of osteopontin and runx-2 were found to be higher on BGS-7 than on HA and the control by Western blot. Accordingly, it is predicted that BGS-7 would have high biocompatibility and good osteoconductivity, and presents a possibility as a new

  2. P2X receptors in epithelia

    DEFF Research Database (Denmark)

    Leipziger, Jens Georg

    2015-01-01

    P2X receptors are ubiquitously expressed in all epithelial tissues but their functional roles are less well studied. Here we review the current state of knowledge by focusing on functional effects of P2X receptor in secretory and in absorptive tissues. In glandular tissue like the parotid gland...

  3. Peripheral nerve P2 basic protein and the Guillain-Barre syndrome : In vitro demonstration of P2-specific antibody-secreting cells

    NARCIS (Netherlands)

    Luijten, J.A.F.M.; Jong, W.A.C. de; Demel, R.A.; Heijnen, C.J.; Ballieux, R.E.

    1984-01-01

    An immune response to the peripheral nerve basic protein P2 may be operative in the pathogenesis of the Guillain-Barré syndrome (GBS). A method is described for the purification of P2 of human origin. Purified P2 was used to investigate whether lymphocytes derived from peripheral blood of GBS

  4. Important roles of P2Y receptors in the inflammation and cancer of digestive system

    OpenAIRE

    Wan, Han-Xing; Hu, Jian-Hong; Xie, Rei; Yang, Shi-Ming; Dong, Hui

    2016-01-01

    Purinergic signaling is important for many biological processes in humans. Purinoceptors P2Y are widely distributed in human digestive system and different subtypes of P2Y receptors mediate different physiological functions from metabolism, proliferation, differentiation to apoptosis etc. The P2Y receptors are essential in many gastrointestinal functions and also involve in the occurrence of some digestive diseases. Since different subtypes of P2Y receptors are present on the same cell of dig...

  5. Accelerated FoxP2 evolution in echolocating bats.

    Directory of Open Access Journals (Sweden)

    Gang Li

    Full Text Available FOXP2 is a transcription factor implicated in the development and neural control of orofacial coordination, particularly with respect to vocalisation. Observations that orthologues show almost no variation across vertebrates yet differ by two amino acids between humans and chimpanzees have led to speculation that recent evolutionary changes might relate to the emergence of language. Echolocating bats face especially challenging sensorimotor demands, using vocal signals for orientation and often for prey capture. To determine whether mutations in the FoxP2 gene could be associated with echolocation, we sequenced FoxP2 from echolocating and non-echolocating bats as well as a range of other mammal species. We found that contrary to previous reports, FoxP2 is not highly conserved across all nonhuman mammals but is extremely diverse in echolocating bats. We detected divergent selection (a change in selective pressure at FoxP2 between bats with contrasting sonar systems, suggesting the intriguing possibility of a role for FoxP2 in the evolution and development of echolocation. We speculate that observed accelerated evolution of FoxP2 in bats supports a previously proposed function in sensorimotor coordination.

  6. The role of P2X receptors in bone biology.

    Science.gov (United States)

    Jørgensen, N R; Syberg, S; Ellegaard, M

    2015-01-01

    Bone is a highly dynamic organ, being constantly modeled and remodeled in order to adapt to the changing need throughout life. Bone turnover involves the coordinated actions of bone formation and bone degradation. Over the past decade great effort has been put into the examination of how P2X receptors regulate bone metabolism and especially for the P2X7 receptor an impressive amount of evidence has now documented its expression in osteoblasts, osteoclasts, and osteocytes as well as important functional roles in proliferation, differentiation, and function of the cells of bone. Key evidence has come from studies on murine knockout models and from pharmacologic studies on cells and animals. More recently, the role of P2X receptors in human bone diseases has been documented. Loss-of-functions polymorphisms in the P2X7 receptorare associated with bone loss and increased fracture risk. Very recently a report from a genetic study in multiple myeloma demonstrated that decreased P2X7 receptor function was associated with increased risk of developing multiple myeloma. In contrast, the risk of developing myeloma bone disease and subsequent vertebral fractures was increased in subjects carrying P2X7 receptor gain-of-function alleles as compared to subjects only carrying loss-of-function or normal functioning alleles. It is evident that P2X receptors are important in regulating bone turnover and maintaining bone mass, and thereby holding great potential as novel drug targets for treatment of bone diseases. However, further research is needed before we fully understand the roles and effects of P2X receptors in bone.

  7. Regulation of human cerebro-microvascular endothelial baso-lateral adhesion and barrier function by S1P through dual involvement of S1P1 and S1P2 receptors.

    Science.gov (United States)

    Wiltshire, Rachael; Nelson, Vicky; Kho, Dan Ting; Angel, Catherine E; O'Carroll, Simon J; Graham, E Scott

    2016-01-27

    Herein we show that S1P rapidly and acutely reduces the focal adhesion strength and barrier tightness of brain endothelial cells. xCELLigence biosensor technology was used to measure focal adhesion, which was reduced by S1P acutely and this response was mediated through both S1P1 and S1P2 receptors. S1P increased secretion of several pro-inflammatory mediators from brain endothelial cells. However, the magnitude of this response was small in comparison to that mediated by TNFα or IL-1β. Furthermore, S1P did not significantly increase cell-surface expression of any key cell adhesion molecules involved in leukocyte recruitment, included ICAM-1 and VCAM-1. Finally, we reveal that S1P acutely and dynamically regulates microvascular endothelial barrier tightness in a manner consistent with regulated rapid opening followed by closing and strengthening of the barrier. We hypothesise that the role of the S1P receptors in this process is not to cause barrier dysfunction, but is related to controlled opening of the endothelial junctions. This was revealed using real-time measurement of barrier integrity using ECIS ZΘ TEER technology and endothelial viability using xCELLigence technology. Finally, we show that these responses do not occur simply though the pharmacology of a single S1P receptor but involves coordinated action of S1P1 and S1P2 receptors.

  8. Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Mononuclear Cells Using Sendai Virus.

    Science.gov (United States)

    Soares, Filipa A C; Pedersen, Roger A; Vallier, Ludovic

    2016-01-01

    This protocol describes the efficient isolation of peripheral blood mononuclear cells from circulating blood via density gradient centrifugation and subsequent generation of integration-free human induced pluripotent stem cells. Peripheral blood mononuclear cells are cultured for 9 days to allow expansion of the erythroblast population. The erythroblasts are then used to derive human induced pluripotent stem cells using Sendai viral vectors, each expressing one of the four reprogramming factors Oct4, Sox2, Klf4, and c-Myc.

  9. Generation of iPSC line epiHUVEC from human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Peggy Matz

    2015-11-01

    Full Text Available Human umbilical vein endothelial cells (HUVECs were used to generate the iPSC line epiHUVEC employing a combination of three episomal-based plasmids expressing OCT4, SOX2, NANOG, LIN28, c-MYC and KLF4. Pluripotency was confirmed both in vivo and in vitro. The transcriptome profile of epiHUVEC and the human embryonic stem cell line — H1 have a Pearson correlation of 0.899.

  10. Generation of iPSC lines from primary human chorionic villi cells

    Directory of Open Access Journals (Sweden)

    Björn Lichtner

    2015-11-01

    Full Text Available Primary human chorionic villi (CV cells were used to generate the iPSC line by retroviral transduction of the four Yamanaka-factors OCT4, SOX2, KLF4 and c-MYC. Pluripotency was confirmed both in vivo and in vitro. The transcriptomes of the CV-derived iPSC lines and the human embryonic stem cell lines—H1 and H9 have a Pearson correlation of 0.929 and 0.943 respectively.

  11. Thermoelastic properties of Zn3P2

    DEFF Research Database (Denmark)

    Gerward, Leif; Olsen, J. Staun; Waśkowska, A.

    2011-01-01

    The bulk modulus and thermal expansion of Zn3P2 has been investigated at pressures up to 21GPa and temperatures down to 100K. The experimental zero-pressure bulk modulus is 80.7 ± 1.8GPa, in accordance with the bulk modulus scaling and lattice properties of the related compound Cd3P2. A tetragonal...... to orthorhombic phase transformation occurs above 11GPa with a relative volume change of-7.1%. Values for the thermal expansion coefficient are reported at 293, 200 and 100K....

  12. P2X Receptors and Synaptic Plasticity

    Czech Academy of Sciences Publication Activity Database

    Pankratov, Y.; Lalo, U.; Krishtal, A.; Verkhratsky, Alexei

    2009-01-01

    Roč. 158, č. 1 (2009), s. 137-148 ISSN 0306-4522 Institutional research plan: CEZ:AV0Z50390512 Keywords : ATP * P2X receptors * synaptic plasticity Subject RIV: FH - Neurology Impact factor: 3.292, year: 2009

  13. Gene-by-environment effect of house dust mite on purinergic receptor P2Y12 (P2RY12) and lung function in children with asthma.

    Science.gov (United States)

    Bunyavanich, S; Boyce, J A; Raby, B A; Weiss, S T

    2012-02-01

    Distinct receptors likely exist for leukotriene (LT)E(4), a potent mediator of airway inflammation. Purinergic receptor P2Y12 is needed for LTE(4)-induced airways inflammation, and P2Y12 antagonism attenuates house dust mite-induced pulmonary eosinophilia in mice. Although experimental data support a role for P2Y12 in airway inflammation, its role in human asthma has never been studied. To test for association between variants in the P2Y12 gene (P2RY12) and lung function in human subjects with asthma, and to examine for gene-by-environment interaction with house dust mite exposure. Nineteen single nucleotide polymorphisms (SNPs) in P2RY12 were genotyped in 422 children with asthma and their parents (n = 1266). Using family based methods, we tested for associations between these SNPs and five lung function measures. We performed haplotype association analyses and tested for gene-by-environment interactions using house dust mite exposure. We used the false discovery rate to account for multiple comparisons. Five SNPs in P2RY12 were associated with multiple lung function measures (P-values 0.006–0.025). Haplotypes in P2RY12 were also associated with lung function (P-values 0.0055–0.046). House dust mite exposure modulated associations between P2RY12 and lung function, with minor allele homozygotes exposed to house dust mite demonstrating worse lung function than those unexposed (significant interaction P-values 0.0028–0.040). The P2RY12 variants were associated with lung function in a large family-based asthma cohort. House dust mite exposure caused significant gene-by-environment effects. Our findings add the first human evidence to experimental data supporting a role for P2Y12 in lung function. P2Y12 could represent a novel target for asthma treatment.

  14. Microglia P2Y13 Receptors Prevent Astrocyte Proliferation Mediated by P2Y1 Receptors

    Directory of Open Access Journals (Sweden)

    Clara Quintas

    2018-05-01

    Full Text Available Cerebral inflammation is a common feature of several neurodegenerative diseases that requires a fine interplay between astrocytes and microglia to acquire appropriate phenotypes for an efficient response to neuronal damage. During brain inflammation, ATP is massively released into the extracellular medium and converted into ADP. Both nucleotides acting on P2 receptors, modulate astrogliosis through mechanisms involving microglia-astrocytes communication. In previous studies, primary cultures of astrocytes and co-cultures of astrocytes and microglia were used to investigate the influence of microglia on astroglial proliferation induced by ADPβS, a stable ADP analog. In astrocyte cultures, ADPβS increased cell proliferation through activation of P2Y1 and P2Y12 receptors, an effect abolished in co-cultures (of astrocytes with ∼12.5% microglia. The possibility that the loss of the ADPβS-mediated effect could have been caused by a microglia-induced degradation of ADPβS or by a preferential microglial localization of P2Y1 or P2Y12 receptors was excluded. Since ADPβS also activates P2Y13 receptors, the contribution of microglial P2Y13 receptors to prevent the proliferative effect of ADPβS in co-cultures was investigated. The results obtained indicate that P2Y13 receptors are low expressed in astrocytes and mainly expressed in microglia. Furthermore, in co-cultures, ADPβS induced astroglial proliferation in the presence of the selective P2Y13 antagonist MRS 2211 (3 μM and of the selective P2Y12 antagonist AR-C66096 (0.1 μM, suggesting that activation of microglial P2Y12 and P2Y13 receptors may induce the release of messengers that inhibit astroglial proliferation mediated by P2Y1,12 receptors. In this microglia-astrocyte paracrine communication, P2Y12 receptors exert opposite effects in astroglial proliferation as a result of its cellular localization: cooperating in astrocytes with P2Y1 receptors to directly stimulate proliferation and in

  15. Python passive network mapping P2NMAP

    CERN Document Server

    Hosmer, Chet

    2015-01-01

    Python Passive Network Mapping: P2NMAP is the first book to reveal a revolutionary and open source method for exposing nefarious network activity. The ""Heartbleed"" vulnerability has revealed significant weaknesses within enterprise environments related to the lack of a definitive mapping of network assets. In Python Passive Network Mapping, Chet Hosmer shows you how to effectively and definitively passively map networks. Active or probing methods to network mapping have traditionally been used, but they have many drawbacks - they can disrupt operations, crash systems, and - most important

  16. Track reconstruction for the P2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Tyukin, Alexey [JGU, Mainz (Germany); Collaboration: P2-Collaboration

    2016-07-01

    The P2 experiment at the future MESA accelerator in Mainz will measure elastically scattered electrons from a hydrogen or lead target in order to determine the parity violating asymmetry for different beam polarisations, which is created due to the weak charge of the target. The asymmetry can provide access to the Weinberg angle and the neutron skin of heavy nuclei. These quantities depend heavily on the momentum transfer Q{sup 2}, thus a reconstruction of single electron tracks in an inhomogeneous magnetic field is necessary. For this, the P2 detector will have four tracking planes of thin high voltage monolithic active pixel sensors (HV-MAPS). The scattered electrons propagate through a magnetic field and hit all four planes. In order to fit the hit positions the General Broken Lines method is used. As a fast propagator, a variation of the Runge-Kutta algorithm is applied, which solves the equation of motion in an inhomogeneous magnetic field numerically, such that the final state momentum and scattering angle can be reconstructed. The initial momentum and incident angle can vary strongly due to the thickness of the target, limiting the reconstruction quality. The average single track Q{sup 2} value of 0.006 GeV{sup 2}/c{sup 2} can be reconstructed with about 4 % uncertainty in a first analysis of the Geant4 simulation, leading to a high total precision due to large electron numbers in the experiment.

  17. Identification of 6H1 as a P2Y purinoceptor: P2Y5.

    Science.gov (United States)

    Webb, T E; Kaplan, M G; Barnard, E A

    1996-02-06

    We have determined the identity of the orphan G-protein coupled receptor cDNA, 6H1, present in activated chicken T cells, as a subtype of P2Y purinoceptor. This identification is based on first on the degree of sequence identity shared with recently cloned members of the P2Y receptor family and second on the pharmacological profile. Upon transient expression in COS-7 cells the 6H1 receptor bound the radiolabel [35S]dATP alpha S specifically and with high affinity (Kd, 10 nM). This specific binding could be competitively displaced by a range of ligands active at P2 purinoceptors, with ATP being the most active (K (i)), 116 nM). Such competition studies have established the following rank order of activity: ATP ADP 2-methylthioATP alpha, beta-methylene ATP, UTP, thus confirming 6H1 as a member of the growing family of P2Y purinoceptors. As the fifth receptor of this type to be identified we suggest that it be named P2Y5.

  18. Dual roles for coactivator activator and its counterbalancing isoform coactivator modulator in human kidney cell tumorigenesis.

    Science.gov (United States)

    Kang, Yun Kyoung; Schiff, Rachel; Ko, Lan; Wang, Tao; Tsai, Sophia Y; Tsai, Ming-Jer; O'Malley, Bert W

    2008-10-01

    Coactivator activator (CoAA) has been reported to be a coactivator that regulates steroid receptor-mediated transcription and alternative RNA splicing. Herein, we show that CoAA is a dual-function coregulator that inhibits G(1)-S transition in human kidney cells and suppresses anchorage-independent growth and xenograft tumor formation. Suppression occurs in part by down-regulating c-myc and its downstream effectors ccnd1 and skp2 and causing accumulation of p27/Kip1 protein. In this cellular setting, CoAA directly represses the proto-oncogene c-myc by recruiting HDAC3 protein and decreasing both the acetylation of histone H3 and the presence of RNA polymerase II on the c-myc promoter. Interestingly, a splicing isoform of CoAA, coactivator modulator (CoAM), antagonizes CoAA-induced G(1)-S transition and growth inhibition by negatively regulating the mRNA levels of the endogenous CoAA isoform. In addition, we found that expression of CoAA protein is significantly decreased in human renal cell carcinoma compared with normal kidney. Our study presents evidence that CoAA is a potential tumor suppressor in renal carcinoma and that CoAM is a counterbalancing splice isoform. This is, thus far, the only example of a nuclear receptor coregulator involved in suppression of kidney cancer and suggests potentially significant new roles for coregulators in renal cancer biology.

  19. Purinergic P2Y12 Receptor Activation in Eosinophils and the Schistosomal Host Response.

    Science.gov (United States)

    Muniz, Valdirene S; Baptista-Dos-Reis, Renata; Benjamim, Claudia F; Mata-Santos, Hilton A; Pyrrho, Alexandre S; Strauch, Marcelo A; Melo, Paulo A; Vicentino, Amanda R R; Silva-Paiva, Juliana; Bandeira-Melo, Christianne; Weller, Peter F; Figueiredo, Rodrigo T; Neves, Josiane S

    2015-01-01

    Identifying new target molecules through which eosinophils secrete their stored proteins may reveal new therapeutic approaches for the control of eosinophilic disorders such as host immune responses to parasites. We have recently reported the expression of the purinergic P2Y12 receptor (P2Y12R) in human eosinophils; however, its functional role in this cell type and its involvement in eosinophilic inflammation remain unknown. Here, we investigated functional roles of P2Y12R in isolated human eosinophils and in a murine model of eosinophilic inflammation induced by Schistosoma mansoni (S. mansoni) infection. We found that adenosine 5'-diphosphate (ADP) induced human eosinophils to secrete eosinophil peroxidase (EPO) in a P2Y12R dependent manner. However, ADP did not interfere with human eosinophil apoptosis or chemotaxis in vitro. In vivo, C57Bl/6 mice were infected with cercariae of the Belo Horizonte strain of S. mansoni. Analyses performed 55 days post infection revealed that P2Y12R blockade reduced the granulomatous hepatic area and the eosinophilic infiltrate, collagen deposition and IL-13/IL-4 production in the liver without affecting the parasite oviposition. As found for humans, murine eosinophils also express the P2Y12R. P2Y12R inhibition increased blood eosinophilia, whereas it decreased the bone marrow eosinophil count. Our results suggest that P2Y12R has an important role in eosinophil EPO secretion and in establishing the inflammatory response in the course of a S. mansoni infection.

  20. Functional and molecular evidence for heteromeric association of P2Y1 receptor with P2Y2 and P2Y4 receptors in mouse granulocytes.

    Science.gov (United States)

    Ribeiro-Filho, Antonio Carlos; Buri, Marcus Vinicius; Barros, Carlos Castilho; Dreyfuss, Juliana Luporini; Nader, Helena Bonciani; Justo, Giselle Zenker; Craveiro, Rogério Bastos; Pesquero, João Bosco; Miranda, Antonio; Ferreira, Alice Teixeira; Paredes-Gamero, Edgar Julian

    2016-07-07

    All hematopoietic cells express P2 receptors, however pharmacological characteristics such as expression and affinity in granulocytes are unknown. Pharmacological characteristics of P2 receptors were evaluated by Ca(2+) measurements using Fura-2 fluorophore. P2 receptors expression were analyzed by flow cytometry and RT-PCR. P2 interaction were shown by coimmunoprecipitation, western blotting and FRET. Granulocytes were responsive to P2Y agonists, whereas P2X agonists were ineffective. Ca(2+) increase, elicited by ADP and UTP was dependent on intracellular stocks and sensitive to G-coupled receptor inhibition. Moreover, MRS2179, a specific antagonist of the P2Y1 receptor, abolished ADP response. Interestingly, ADP and UTP exhibited full heterologous desensitization, suggesting that these agonists interact with the same receptor. The heteromeric association between P2Y1 receptor and the P2Y2 and P2Y4 receptors was shown by immunoprecipitation and FRET analysis. Clear evidence of heteromeric association of P2Y receptors was found during the evaluation of P2 receptors present in mice granulocytes, which could impact in the classical pharmacology of P2Y receptors in granulocytes.

  1. Managing P2P services via the IMS

    NARCIS (Netherlands)

    Liotta, A.; Lin, L.

    2007-01-01

    The key aim of our work was to illustrate the benefits and means to deploy P2P services via the IMS. Having demonstrated the technical viability of P2P-IMS we have also found a way to add a new management dimension to existing P2P systems. P2P-IMS comes with a natural "data management" mechanism,

  2. Dual roles for CoAA and its counterbalancing isoform CoAM in human kidney cell tumorigenesis

    Science.gov (United States)

    Kang, Yun Kyoung; Schiff, Rachel; Ko, Lan; Wang, Tao; Tsai, Sophia Y.; Tsai, Ming-Jer; W. O’Malley, Bert

    2008-01-01

    Co-Activator Activator (CoAA) has been reported to be a coactivator that regulates steroid receptor-mediated transcription and alternative RNA splicing. Herein we show that CoAA is a dual-function coregulator that inhibits G1/S transition in human kidney cells and suppresses anchorage independent growth and xenograft tumor formation. Suppression occurs in part by downregulating c-myc and its downstream effectors ccnd1 and skp2, and causing accumulation of p27/Kip1 protein. In this cellular setting, CoAA directly represses the proto-oncogene, c-myc by recruiting HDAC3 protein and decreasing both the acetylation of histone H3 and the presence of RNA polymerase II on the c-myc promoter. Interestingly, a splicing isoform of CoAA, Coactivator Modulator (CoAM), antagonizes CoAA-induced G1/S transition and growth inhibition by negatively regulating the mRNA levels of the endogenous CoAA isoform. In addition, we found that expression of CoAA protein is significantly decreased in human renal cell carcinoma as compared to normal kidney. Our study presents evidence that CoAA is a potential tumor suppressor in renal carcinoma and that CoAM is a counterbalancing splice-isoform. This is so far the only example of a nuclear receptor coregulator involved in suppression of kidney cancer, and suggests potentially significant new roles for coregulators in renal cancer biology. PMID:18829545

  3. Targeting of the P2X7 receptor in pancreatic cancer and stellate cells

    DEFF Research Database (Denmark)

    Giannuzzo, Andrea; Saccomano, Mara; Napp, Joanna

    2016-01-01

    of PDAC. In the in vitro studies we show that human PDAC cells with luciferase gene (PancTu-1 Luc cells) express high levels of P2X7R protein. Allosteric P2X7R antagonist AZ10606120 inhibited cell proliferation in basal conditions, indicating that P2X7R was tonically active. Extracellular ATP and Bz......ATP, to which the P2X7R is more sensitive, further affected cell survival and confirmed complex functionality of P2X7R. PancTu-1 Luc migration and invasion was reduced by AZ10606120, and it was stimulated by PSCs, but not by PSCs from P2X7(-/-) animals. PancTu-1 Luc cells were orthotopically transplanted...

  4. P2X7 on mouse T cells: one channel, many functions

    Directory of Open Access Journals (Sweden)

    Björn eRissiek

    2015-05-01

    Full Text Available The P2X7 receptor is an adenosine triphosphate (ATP-gated cation channel that is expressed by several cells of the immune system. P2X7 is best known for its proinflammatory role in promoting inflammasome formation and release of mature IL-1β by innate immune cells. Mounting evidence indicates that P2X7 is also an important regulatory receptor of murine and human T cell functions. Murine T cells express a sensitive splice variant of P2X7 that can be activated either by non-covalent binding of ATP or, in the presence of nicotinamide adenine dinucleotide (NAD+, by its covalent ADP-ribosylation catalyzed by the ecto-ADP-ribosyltransferase ARTC2.2. Prolonged activation of P2X7 by either one of these pathways triggers the induction of T cell death. Conversely, lower concentrations of ATP can activate P2X7 to enhance T cell proliferation and production of IL-2. In this review we will highlight the molecular and cellular consequences of P2X7 activation on mouse T cells and its versatile role in T cell homeostasis and activation. Further, we will discuss important differences in the function of P2X7 on human and murine T cells.

  5. Structural and Molecular Modeling Features of P2X Receptors

    Directory of Open Access Journals (Sweden)

    Luiz Anastacio Alves

    2014-03-01

    Full Text Available Currently, adenosine 5'-triphosphate (ATP is recognized as the extracellular messenger that acts through P2 receptors. P2 receptors are divided into two subtypes: P2Y metabotropic receptors and P2X ionotropic receptors, both of which are found in virtually all mammalian cell types studied. Due to the difficulty in studying membrane protein structures by X-ray crystallography or NMR techniques, there is little information about these structures available in the literature. Two structures of the P2X4 receptor in truncated form have been solved by crystallography. Molecular modeling has proven to be an excellent tool for studying ionotropic receptors. Recently, modeling studies carried out on P2X receptors have advanced our knowledge of the P2X receptor structure-function relationships. This review presents a brief history of ion channel structural studies and shows how modeling approaches can be used to address relevant questions about P2X receptors.

  6. P2Y6 Receptor Activation Promotes Inflammation and Tissue Remodeling in Pulmonary Fibrosis

    Science.gov (United States)

    Müller, Tobias; Fay, Susanne; Vieira, Rodolfo Paula; Karmouty-Quintana, Harry; Cicko, Sanja; Ayata, Cemil Korcan; Zissel, Gernot; Goldmann, Torsten; Lungarella, Giuseppe; Ferrari, Davide; Di Virgilio, Francesco; Robaye, Bernard; Boeynaems, Jean-Marie; Lazarowski, Eduardo R.; Blackburn, Michael R.; Idzko, Marco

    2017-01-01

    Idiopathic pulmonary fibrosis (IPF) is a disease with a poor prognosis and very few available treatment options. The involvement of the purinergic receptor subtypes P2Y2 and P2X7 in fibrotic lung disease has been demonstrated recently. In this study, we investigated the role of P2Y6 receptors in the pathogenesis of IPF in humans and in the animal model of bleomycin-induced lung injury. P2Y6R expression was upregulated in lung structural cells but not in bronchoalveolar lavage (BAL) cells derived from IPF patients as well as in animals following bleomycin administration. Furthermore, BAL fluid levels of the P2Y6R agonist uridine-5′-diphosphate were elevated in animals with bleomycin-induced pulmonary fibrosis. Inflammation and fibrosis following bleomycin administration were reduced in P2Y6R-deficient compared to wild-type animals confirming the pathophysiological relevance of P2Y6R subtypes for fibrotic lung diseases. Experiments with bone marrow chimeras revealed the importance of P2Y6R expression on lung structural cells for pulmonary inflammation and fibrosis. Similar effects were obtained when animals were treated with the P2Y6R antagonist MRS2578. In vitro studies demonstrated that proliferation and secretion of the pro-inflammatory/pro-fibrotic cytokine IL-6 by lung fibroblasts are P2Y6R-mediated processes. In summary, our results clearly demonstrate the involvement of P2Y6R subtypes in the pathogenesis of pulmonary fibrosis. Thus, blocking pulmonary P2Y6 receptors might be a new target for the treatment of IPF. PMID:28878780

  7. P2Y6 Receptor Activation Promotes Inflammation and Tissue Remodeling in Pulmonary Fibrosis

    Directory of Open Access Journals (Sweden)

    Tobias Müller

    2017-08-01

    Full Text Available Idiopathic pulmonary fibrosis (IPF is a disease with a poor prognosis and very few available treatment options. The involvement of the purinergic receptor subtypes P2Y2 and P2X7 in fibrotic lung disease has been demonstrated recently. In this study, we investigated the role of P2Y6 receptors in the pathogenesis of IPF in humans and in the animal model of bleomycin-induced lung injury. P2Y6R expression was upregulated in lung structural cells but not in bronchoalveolar lavage (BAL cells derived from IPF patients as well as in animals following bleomycin administration. Furthermore, BAL fluid levels of the P2Y6R agonist uridine-5′-diphosphate were elevated in animals with bleomycin-induced pulmonary fibrosis. Inflammation and fibrosis following bleomycin administration were reduced in P2Y6R-deficient compared to wild-type animals confirming the pathophysiological relevance of P2Y6R subtypes for fibrotic lung diseases. Experiments with bone marrow chimeras revealed the importance of P2Y6R expression on lung structural cells for pulmonary inflammation and fibrosis. Similar effects were obtained when animals were treated with the P2Y6R antagonist MRS2578. In vitro studies demonstrated that proliferation and secretion of the pro-inflammatory/pro-fibrotic cytokine IL-6 by lung fibroblasts are P2Y6R-mediated processes. In summary, our results clearly demonstrate the involvement of P2Y6R subtypes in the pathogenesis of pulmonary fibrosis. Thus, blocking pulmonary P2Y6 receptors might be a new target for the treatment of IPF.

  8. Important roles of P2Y receptors in the inflammation and cancer of digestive system.

    Science.gov (United States)

    Wan, Han-Xing; Hu, Jian-Hong; Xie, Rei; Yang, Shi-Ming; Dong, Hui

    2016-05-10

    Purinergic signaling is important for many biological processes in humans. Purinoceptors P2Y are widely distributed in human digestive system and different subtypes of P2Y receptors mediate different physiological functions from metabolism, proliferation, differentiation to apoptosis etc. The P2Y receptors are essential in many gastrointestinal functions and also involve in the occurrence of some digestive diseases. Since different subtypes of P2Y receptors are present on the same cell of digestive organs, varying subtypes of P2Y receptors may have opposite or synergetic functions on the same cell. Recently, growing lines of evidence strongly suggest the involvement of P2Y receptors in the pathogenesis of several digestive diseases. In this review, we will focus on their important roles in the development of digestive inflammation and cancer. We anticipate that as the special subtypes of P2Y receptors are studied in depth, specific modulators for them will have good potentials to become promising new drugs to treat human digestive diseases in the near future.

  9. Investigating the Role of the Post-transcriptional Gene Regulator MiR-24-3p in the Proliferation, Migration and Apoptosis of Human Arterial Smooth Muscle Cells in Arteriosclerosis Obliterans

    Directory of Open Access Journals (Sweden)

    Xiao-feng Zhu

    2015-07-01

    Full Text Available Aims: To explore the expression of miR-24-3p in human arteries with arteriosclerosis obliterans (ASO as well as the role of miR-24-3p in the pathogenesis of ASO. Methods: We used quantitative real-time PCR (qRT-PCR and in situ hybridization to monitor miR-24-3p expression in human arteries. To investigate the effect of miR-24-3p on human arterial smooth muscle cells (HASMCs, we applied cell counting and EdU assays to monitor proliferation and transwell and wound healing assays to investigate migration and flow cytometry to investigate apoptosis. Furthermore, we applied 3'-untranslated region (3'-UTR luciferase assays to investigate the role of miR-24-3p in targeting platelet-derived growth factor receptor B (PDGFRB and c-Myc. Results: MiR-24-3p was mainly located in the media of arteries and was downregulated in ASO arteries compared with normal arteries. Platelet-derived growth factor BB (PDGF-BB treatment reduced the expression of miR-24-3p in primary cultured HASMCs. MiR-24-3p mimic oligos inhibited the proliferation and migration, and promotes apoptosis of HASMCs. Our 3'-UTR luciferase assays confirmed that PDGFRB and c-Myc were targets of miR-24-3p. Conclusion: The results suggest that miR-24-3p regulates the proliferation and migration of HASMCs by targeting PDGFRB and c-Myc. The PDGF/miR-24-3p/PDGFRB and PDGF/miR-24-3p/c-Myc pathways may play critical roles in the pathogenesis of ASO. These findings highlight the potential for new therapeutic targets for ASO.

  10. Functional polymorphisms in the P2X7 receptor gene are associated with osteoporosis

    DEFF Research Database (Denmark)

    Husted, L B; Harsløf, T; Stenkjær, L

    2013-01-01

    variant allele, which has been associated with increased receptor function in monocytes, was associated with increased total hip BMD in women. With the exception of His155Tyr for which we found conflicting results in men and women, our results are consistent with the phenotype of the knockout mouse......UNLABELLED: The P2X(7) receptor is an ATP-gated cation channel. We investigated the effect of both loss-of-function and gain-of-function polymorphisms in the P2X(7) receptor gene on BMD and risk of vertebral fractures and found that five polymorphisms and haplotypes containing three...... of these polymorphisms were associated with BMD and fracture risk. INTRODUCTION: The P2X(7) receptor is an ATP-gated cation channel. P2X(7) receptor knockout mice have reduced total bone mineral content, and because several functional polymorphisms have been identified in the human P2X(7) receptor gene, we wanted...

  11. Network-Aware DHT-Based P2P Systems

    Science.gov (United States)

    Fayçal, Marguerite; Serhrouchni, Ahmed

    P2P networks lay over existing IP networks and infrastructure. This chapter investigates the relation between both layers, details the motivations for network awareness in P2P systems, and elucidates the requirements P2P systems have to meet for efficient network awareness. Since new P2P systems are mostly based on DHTs, we also present and analyse DHT-based architectures. And after a brief presentation of different existing network-awareness solutions, the chapter goes on effective cooperation between P2P traffic and network providers' business agreements, and introduces emerging DHT-based P2P systems that are network aware through a semantic defined for resource sharing. These new systems ensure also a certain context-awareness. So, they are analyzed and compared before an open end on prospects of network awareness in P2P systems.

  12. Risk Management of P2P Internet Financing Service Platform

    Science.gov (United States)

    Yalei, Li

    2017-09-01

    Since 2005, the world’s first P2P Internet financing service platform Zopa in UK was introduced, in the development of “Internet +” trend, P2P Internet financing service platform has been developed rapidly. In 2007, China’s first P2P platform “filming loan” was established, marking the P2P Internet financing service platform to enter China and the rapid development. At the same time, China’s P2P Internet financing service platform also appeared in different forms of risk. This paper focuses on the analysis of the causes of risk of P2P Internet financing service platform and the performance of risk management process. It provides a solution to the Internet risk management plan, and explains the risk management system of the whole P2P Internet financing service platform and the future development direction.

  13. Differential endosomal sorting of a novel P2Y12 purinoreceptor mutant.

    Science.gov (United States)

    Cunningham, Margaret R; Nisar, Shaista P; Cooke, Alexandra E; Emery, Elizabeth D; Mundell, Stuart J

    2013-05-01

    P2Y12 receptor internalization and recycling play an essential role in ADP-induced platelet activation. Recently, we identified a patient with a mild bleeding disorder carrying a heterozygous mutation of P2Y12 (P341A) whose P2Y12 receptor recycling was significantly compromised. Using human cell line models, we identified key proteins regulating wild-type (WT) P2Y12 recycling and investigated P2Y12 -P341A receptor traffic. Treatment with ADP resulted in delayed Rab5-dependent internalization of P341A when compared with WT P2Y12 . While WT P2Y12 rapidly recycled back to the membrane via Rab4 and Rab11 recycling pathways, limited P341A recycling was observed, which relied upon Rab11 activity. Although minimal receptor degradation was evident, P341A was localized in Rab7-positive endosomes with considerable agonist-dependent accumulation in the trans-Golgi network (TGN). Rab7 activity is known to facilitate recruitment of retromer complex proteins to endosomes to transport cargo to the TGN. Here, we identified that P341A colocalized with Vps26; depletion of which blocked limited recycling and promoted receptor degradation. This study has identified key points of divergence in the endocytic traffic of P341A versus WT-P2Y12 . Given that these pathways are retained in human platelets, this research helps define the molecular mechanisms regulating P2Y12 receptor traffic and explain the compromised receptor function in the platelets of the P2Y12 -P341A-expressing patient. © 2013 John Wiley & Sons A/S.

  14. Purine receptor P2Y_6 mediates cellular response to γ-ray-induced DNA damage

    International Nuclear Information System (INIS)

    Ide, Shunta; Nishimaki, Naoko; Tsukimoto, Mitsutoshi; Kojima, Shuji

    2014-01-01

    We previously showed that nucleotide P2 receptor agonists such as ATP and UTP amplify γ-ray-induced focus formation of phosphorylated histone H2A variant H2AX (γH2AX), which is considered to be an indicator of DNA damage so far, by activating purine P2Y_6 and P2Y_1_2 receptors. Therefore, we hypothesized that these P2 receptors play a role in inducing the repair response to γ-ray-induced DNA damage. In the present study, we tested this idea by using human lung cancer A549 cells. First, reverse-transcription polymerase chain reaction (RT-PCR) showed that P2Y_6 receptor is highly expressed in A549 cells, but P2Y_1_2 receptor is only weakly expressed. Next, colony formation assay revealed that P2Y_6 receptor antagonist MRS2578 markedly reduced the survival rate of γ-ray-exposed A549 cells. The survival rate was also significantly reduced in P2Y_6-knock-down cells, compared with scramble siRNA-transfected cells. Since it has reported that phosphorylation of ERK1/2 after activation of EGFR via P2Y_6 and P2Y_1_2 receptors is involved in the repair response to γ-ray-induced DNA damage, we next examined whether γ-ray-induced phosphorylation of ERK1/2 was also inhibited by MRS2578 in A549 cells. We found that it was. Taken together, these findings indicate that purinergic signaling through P2Y_6 receptor, followed by ERK1/2 activation, promotes the cellular repair response to γ-ray-induced DNA damage. (author)

  15. Regulation of P2Y1 receptor traffic by sorting Nexin 1 is retromer independent.

    Science.gov (United States)

    Nisar, Shaista; Kelly, Eamonn; Cullen, Pete J; Mundell, Stuart J

    2010-04-01

    The activity and traffic of G-protein coupled receptors (GPCRs) is tightly controlled. Recent work from our laboratory has shown that P2Y(1) and P2Y(12) responsiveness is rapidly and reversibly modulated in human platelets and that the underlying mechanism requires receptor trafficking as an essential part of this process. However, little is known about the molecular mechanisms underlying P2Y receptor traffic. Sorting nexin 1 (SNX1) has been shown to regulate the endosomal sorting of cell surface receptors either to lysosomes where they are downregulated or back to the cell surface. These functions may in part be due to interactions of SNX1 with the mammalian retromer complex. In this study, we investigated the role of SNX1 in P2Y receptor trafficking. We show that P2Y(1) receptors recycle via a slow recycling pathway that is regulated by SNX1, whereas P2Y(12) receptors return to the cell surface via a rapid route that is SNX1 independent. SNX1 inhibition caused a dramatic increase in the rate of P2Y(1) receptor recycling, whereas inhibition of Vps26 and Vps35 known to be present in retromer had no effect, indicating that SNX1 regulation of P2Y(1) receptor recycling is retromer independent. In addition, inhibition of SNX4, 6 and 17 proteins did not affect P2Y(1) receptor recycling. SNX1 has also been implicated in GPCR degradation; however, we provide evidence that P2Y receptor degradation is SNX1 independent. These data describe a novel function of SNX1 in the regulation of P2Y(1) receptor recycling and suggest that SNX1 plays multiple roles in endocytic trafficking of GPCRs.

  16. The P2X7 receptor regulates cell survival, migration and invasion of pancreatic ductal adenocarcinoma cells

    DEFF Research Database (Denmark)

    Giannuzzo, Andrea; Pedersen, Stine Helene Falsig; Novak, Ivana

    2015-01-01

    of the ATP receptors, the P2X7 receptor (P2X7R) could be an important player in PDAC behaviour. METHODS: We determined the expression (real time PCR and Western blot) and localization (immunofluorescence) of P2X7R in human PDAC cell lines (AsPC-1, BxPC-3, Capan-1, MiaPaCa-2, Panc-1) and a "normal" human...

  17. Hyperglycemia-induced Renal P2X7 Receptor Activation Enhances Diabetes-related Injury

    Directory of Open Access Journals (Sweden)

    Robert I. Menzies

    2017-05-01

    Full Text Available Diabetes is a leading cause of renal disease. Glomerular mesangial expansion and fibrosis are hallmarks of diabetic nephropathy and this is thought to be promoted by infiltration of circulating macrophages. Monocyte chemoattractant protein-1 (MCP-1 has been shown to attract macrophages in kidney diseases. P2X7 receptors (P2X7R are highly expressed on macrophages and are essential components of pro-inflammatory signaling in multiple tissues. Here we show that in diabetic patients, renal P2X7R expression is associated with severe mesangial expansion, impaired glomerular filtration (≤40 ml/min/1.73 sq. m., and increased interstitial fibrosis. P2X7R activation enhanced the release of MCP-1 in human mesangial cells cultured under high glucose conditions. In mice, P2X7R-deficiency prevented glomerular macrophage attraction and collagen IV deposition; however, the more severe interstitial inflammation and fibrosis often seen in human diabetic kidney diseases was not modelled. Finally, we demonstrate that a P2X7R inhibitor (AZ11657312 can reduce renal macrophage accrual following the establishment of hyperglycemia in a model of diabetic nephropathy. Collectively these data suggest that P2X7R activation may contribute to the high prevalence of kidney disease found in diabetics.

  18. P2X4: A fast and sensitive purinergic receptor

    Directory of Open Access Journals (Sweden)

    Jaanus Suurväli

    2017-10-01

    Full Text Available Extracellular nucleotides have been recognized as important mediators of activation, triggering multiple responses via plasma membrane receptors known as P2 receptors. P2 receptors comprise P2X ionotropic receptors and G protein-coupled P2Y receptors. P2X receptors are expressed in many tissues, where they are involved in a number of functions including synaptic transmission, muscle contraction, platelet aggregation, inflammation, macrophage activation, differentiation and proliferation, neuropathic and inflammatory pain. P2X4 is one of the most sensitive purinergic receptors (at nanomolar ATP concentrations, about one thousand times more than the archetypal P2X7. P2X4 is widely expressed in central and peripheral neurons, in microglia, and also found in various epithelial tissues and endothelial cells. It localizes on the plasma membrane, but also in intracellular compartments. P2X4 is preferentially localized in lysosomes, where it is protected from proteolysis by its glycosylation. High ATP concentration in the lysosomes does not activate P2X4 at low pH; P2X4 gets activated by intra-lysosomal ATP only in its fully dissociated tetra-anionic form, when the pH increases to 7.4. Thus, P2X4 is functioning as a Ca2+-channel after the fusion of late endosomes and lysosomes. P2X4 modulates major neurotransmitter systems and regulates alcohol-induced responses in microglia. P2X4 is one of the key receptors mediating neuropathic pain. However, injury-induced upregulation of P2X4 expression is gender dependent and plays a key role in pain difference between males and females. P2X4 is also involved in inflammation. Extracellular ATP being a pro-inflammatory molecule, P2X4 can trigger inflammation in response to high ATP release. It is therefore involved in multiple pathologies, like post-ischemic inflammation, rheumatoid arthritis, airways inflammation in asthma, neurodegenerative diseases and even metabolic syndrome. Although P2X4 remains poorly

  19. P2X1 receptors and the endothelium

    Directory of Open Access Journals (Sweden)

    LS Harrington

    2005-03-01

    Full Text Available Adenosine triphosphate (ATP is now established as a principle vaso-active mediator in the vasculature. Its actions on arteries are complex, and are mediated by the P2X and P2Y receptor families. It is generally accepted that ATP induces a bi-phasic response in arteries, inducing contraction via the P2X and P2Y receptors on the smooth muscle cells, and vasodilation via the actions of P2Y receptors located on the endothelium. However, a number of recent studies have placed P2X1 receptors on the endothelium of some arteries. The use of a specific P2X1 receptor ligand, a, b methylene ATP has demonstrated that P2X1 receptors also have a bi-functional role. The actions of ATP on P2X1 receptors is therefore dependant on its location, inducing contraction when located on the smooth muscle cells, and dilation when expressed on the endothelium, comparable to that of P2Y receptors.

  20. (p,2p) experiments at the University of Maryland cyclotron

    International Nuclear Information System (INIS)

    Roos, P.G.

    1976-11-01

    Some of the (p,2p) work which has been carried out at the Maryland Cyclotron is discussed. A brief introduction to the (p,2p) reaction is presented, and the types of experimental techniques utilized in (p,2p) studies are discussed. A brief introduction is given to the various theoretical treatments presently available to analyze (p,2p) reaction data. Secondly, experimental and theoretical studies of (p,2p) on d, 3 He, and 4 He carried out by the Maryland group are presented. Thirdly, (p,2p) results are discussed for 6 Li, 7 Li, and 12 C at 100 MeV. Fourthly, the effects of distortion on the experimental data are considered by presenting theoretical calculations for 12 C and 40 Ca at various bombarding energies

  1. Cryptocurrency Networks: A New P2P Paradigm

    Directory of Open Access Journals (Sweden)

    Sergi Delgado-Segura

    2018-01-01

    Full Text Available P2P networks are the mechanism used by cryptocurrencies to disseminate system information while keeping the whole system as much decentralized as possible. Cryptocurrency P2P networks have new characteristics that propose new challenges and avoid some problems of existing P2P networks. By characterizing the most relevant cryptocurrency network, Bitcoin, we provide details on different properties of cryptocurrency networks and their similarities and differences with standard P2P network paradigms. Our study allows us to conclude that cryptocurrency networks present a new paradigm of P2P networks due to the mechanisms they use to achieve high resilience and security. With this new paradigm, interesting research lines can be further developed, both in the focused field of P2P cryptocurrency networks and also when such networks are combined with other distributed scenarios.

  2. Molecular mechanisms of platelet P2Y(12) receptor regulation.

    Science.gov (United States)

    Cunningham, Margaret R; Nisar, Shaista P; Mundell, Stuart J

    2013-02-01

    Platelets are critical for haemostasis, however inappropriate activation can lead to the development of arterial thrombosis, which can result in heart attack and stroke. ADP is a key platelet agonist that exerts its actions via stimulation of two surface GPCRs (G-protein-coupled receptors), P2Y(1) and P2Y(12). Similar to most GPCRs, P2Y receptor activity is tightly regulated by a number of complex mechanisms including receptor desensitization, internalization and recycling. In the present article, we review the molecular mechanisms that underlie P2Y(1) and P2Y(12) receptor regulation, with particular emphasis on the structural motifs within the P2Y(12) receptor, which are required to maintain regulatory protein interaction. The implications of these findings for platelet responsiveness are also discussed.

  3. Supporting Collaboration and Creativity Through Mobile P2P Computing

    Science.gov (United States)

    Wierzbicki, Adam; Datta, Anwitaman; Żaczek, Łukasz; Rzadca, Krzysztof

    Among many potential applications of mobile P2P systems, collaboration applications are among the most prominent. Examples of applications such as Groove (although not intended for mobile networks), collaboration tools for disaster recovery (the WORKPAD project), and Skype's collaboration extensions, all demonstrate the potential of P2P collaborative applications. Yet, the development of such applications for mobile P2P systems is still difficult because of the lack of middleware.

  4. Controlling P2P File-Sharing Networks Traffic

    OpenAIRE

    García Pineda, Miguel; HAMMOUMI, MOHAMMED; Canovas Solbes, Alejandro; Lloret, Jaime

    2011-01-01

    Since the appearance of Peer-To-Peer (P2P) file-sharing networks some time ago, many Internet users have chosen this technology to share and search programs, videos, music, documents, etc. The total number of P2P file-sharing users has been increasing and decreasing in the last decade depending on the creation or end of some well known P2P file-sharing systems. P2P file-sharing networks traffic is currently overloading some data networks and it is a major headache for netw...

  5. ZrCu2P2 and HfCu2P2 phosphides and their crystal structure

    International Nuclear Information System (INIS)

    Lomnitskaya, Ya.F.

    1986-01-01

    Isostructural ZrCu 2 P 2 and HfCu 2 P 2 compounds are prepared for the first time. X-ray diffraction analysis (of powder, DRON-2.0 diffractometer, FeKsub(α) radiation) was used to study crystal structure of HfCu 2 P 2 phosphide belonging to the CaAl 2 Si 2 structural type (sp. group P anti 3 m 1, R=0.095). Lattice parameters the compounds are as follows: for ZrCu 2 P 2 a=0.3810(1), c=0.6184(5); for HfCu 2 P 2 a=0.3799(1), c=0.6160(2) (nm). Atomic parameters in the HfCu 2 P 2 structure and interatomic distances are determined

  6. The P2X7 ATP receptor modulates renal cyst development in vitro

    International Nuclear Information System (INIS)

    Hillman, Kate A.; Woolf, Adrian S.; Johnson, Tanya M.; Wade, Angela; Unwin, Robert J.; Winyard, Paul J.D.

    2004-01-01

    P2X 7 , a piercing receptor, is expressed in renal collecting ducts as they undergo fulminant cysto genesis in the cpk/cpk mouse model of autosomal recessive polycystic kidney disease (ARPKD). Dissociated cpk/cpk kidneys generate cysts from cell aggregates within 24 h of suspension culture and we demonstrate that BzATP, a P2X 7 agonist, reduces cystogenesis. This effect is P2X 7 -specific, because: (i) equimolar concentrations of other purinergic agonists, ATP and UTP, had lesser effects and (ii) the P2X 7 inhibitor, oxidized ATP, abrogated the BzATP-mediated reduction in cystogenesis. BzATP did not significantly affect total cell number, proliferation, LDH release or caspase 3 activity, and zVAD-fmk, a caspase blocker, failed to modulate BzATP effects. In addition, this P2X 7 agonist did not significantly alter cyst size, probably excluding altered vectorial transport. In vivo, ATP was detected in cyst fluid from cpk/cpk kidneys; moreover, P2X 7 protein was also upregulated in human fetal ARPKD epithelia versus normal fetal collecting ducts. Thus, ATP may inhibit pathological renal cyst growth through P2X 7 signaling

  7. Resource trade-off in P2P streaming

    NARCIS (Netherlands)

    Alhaisoni, M.; Liotta, A.; Ghanbari, M.

    2009-01-01

    P2P TV has emerged as a powerful alternative solution for multimedia streaming over the traditional client-server paradigm. It has proven to be a valid substitute for online applications which offer video-on-demand and real-time video. This is mainly due to the scalability and resiliency that P2P

  8. P2Y2 and P2Y4 receptors regulate pancreatic Ca²+-activated K+ channels differently

    DEFF Research Database (Denmark)

    Klærke, Susanne Edeling Hede; Amstrup, Jan; Klærke, Dan Arne

    2005-01-01

    Extracellular ATP is an important regulator of transepithelial transport in a number of tissues. In pancreatic ducts, we have shown that ATP modulates epithelial K+ channels via purinergic receptors, most likely the P2Y2 and P2Y4 receptors, but the identity of the involved K+ channels was not cle...

  9. Purinergní P2X rodina a specifické vlastnosti P2X7 podtypu

    Czech Academy of Sciences Publication Activity Database

    Jindřichová, Marie; Zemková, Hana

    2013-01-01

    Roč. 62, č. 2 (2013), s. 40-46 ISSN 1210-6313 R&D Projects: GA ČR(CZ) GPP304/12/P371 Institutional support: RVO:67985823 Keywords : extracellular ATP * purinergic P2X family * P2X7 receptor * cell proliferation and apoptosis Subject RIV: ED - Physiology

  10. PPADS: an antagonist at endothelial P2Y-purinoceptors but not P2U-purinoceptors.

    Science.gov (United States)

    Brown, C; Tanna, B; Boarder, M R

    1995-11-01

    1. Bovine aortic endothelial (BAE) cells contain two co-existing receptors for extracellular ATP, the P2Y and P2U-purinoceptors. Here we have determined whether the proposed P2X-purinoceptor antagonist, pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) could distinguish between these two receptor subtypes. 2. Cells labelled with myo-[2-3H]-inositol were stimulated with increasing concentrations of either the P2Y-agonist, 2MeSATP, or the P2U-agonist, UTP in the absence or presence of 30 microM PPADS. The accumulation of total [3H]-inositol (poly)phosphates mediated by 2MeSATP was markedly attenuated by PPADS, whereas the response to UTP was not significantly affected. 3. Stimulation of BAE cells with increasing concentrations of ATP showed a reduced response in the presence of 10 microM PPADS, but this effect of the antagonist was not significant. By contrast, inhibition of the response to ADP was profound and highly significant. 4. These observations show that PPADS is not a selective P2X-purinoceptor antagonist, but is able to distinguish between P2Y- and P2YU-purinoceptors in BAE cells, and indicate that this compound may provide a useful tool in the study of multiple subtypes of P2-purinoceptors. Furthermore the results are consistent with the hypothesis that ATP interacts with both receptor subtypes, but that the action of ADP is primarily at the P2Y-purinoceptor in these endothelial cells.

  11. Comparing Pedophile Activity in Different P2P Systems

    OpenAIRE

    Raphaël Fournier; Thibault Cholez; Matthieu Latapy; Isabelle Chrisment; Clémence Magnien; Olivier Festor; Ivan Daniloff

    2014-01-01

    International audience; Peer-to-peer (P2P) systems are widely used to exchange content over the Internet. Knowledge of pedophile activity in such networks remains limited, despite having important social consequences. Moreover, though there are different P2P systems in use, previous academic works on this topic focused on one system at a time and their results are not directly comparable. We design a methodology for comparing KAD and eDonkey, two P2P systems among the most prominent ones and ...

  12. P2X receptors, sensory neurons and pain.

    Science.gov (United States)

    Bele, Tanja; Fabbretti, Elsa

    2015-01-01

    Pain represents a very large social and clinical problem since the current treatment provides insufficient pain relief. Plasticity of pain receptors together with sensitisation of sensory neurons, and the role of soluble mediators released from non-neuronal cells render difficult to understand the spatial and temporal scale of pain development, neuronal responses and disease progression. In pathological conditions, ATP is one of the most powerful mediators that activates P2X receptors that behave as sensitive ATP-detectors, such as neuronal P2X3 receptor subtypes and P2X4 and P2X7 receptors expressed on non-neuronal cells. Dissecting the molecular mechanisms occurring in sensory neurons and in accessory cells allows to design appropriate tissue- and cell- targeted approaches to treat chronic pain.

  13. Tetravalent one-regular graphs of order 4p2

    DEFF Research Database (Denmark)

    Feng, Yan-Quan; Kutnar, Klavdija; Marusic, Dragan

    2014-01-01

    A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified.......A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified....

  14. Meeting of the ITER SWG-P2 in Vienna

    International Nuclear Information System (INIS)

    Pinkau, K.; Kishimoto, H.

    1999-01-01

    The Special Working Group established under Protocol 2 to the ITER IDA Agreement (SWG-P2) met at the IAEA in Vienna in 6-9 December 1999. This report contains excerpts from the report of the ITER SWG-P2 to the ITER Council on the Joint Implementation of ITER, detailing benefits, contributions, the legal framework, siting, licensing and decommissioning as well as procurement, staffing and intellectual property rights

  15. Data Sharing in DHT Based P2P Systems

    Science.gov (United States)

    Roncancio, Claudia; Del Pilar Villamil, María; Labbé, Cyril; Serrano-Alvarado, Patricia

    The evolution of peer-to-peer (P2P) systems triggered the building of large scale distributed applications. The main application domain is data sharing across a very large number of highly autonomous participants. Building such data sharing systems is particularly challenging because of the “extreme” characteristics of P2P infrastructures: massive distribution, high churn rate, no global control, potentially untrusted participants... This article focuses on declarative querying support, query optimization and data privacy on a major class of P2P systems, that based on Distributed Hash Table (P2P DHT). The usual approaches and the algorithms used by classic distributed systems and databases for providing data privacy and querying services are not well suited to P2P DHT systems. A considerable amount of work was required to adapt them for the new challenges such systems present. This paper describes the most important solutions found. It also identifies important future research trends in data management in P2P DHT systems.

  16. P2P Data Management in Mobile Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Nida Sahar Sayeda

    2013-04-01

    Full Text Available The rapid growth in wireless technologies has made wireless communication an important source for transporting data across different domains. In the same way, there are possibilities of many potential applications that can be deployed using WSNs (Wireless Sensor Networks. However, very limited applications are deployed in real life due to the uncertainty and dynamics of the environment and scare resources. This makes data management in WSN a challenging area to find an approach that suits its characteristics. Currently, the trend is to find efficient data management schemes using evolving technologies, i.e. P2P (Peer-to-Peer systems. Many P2P approaches have been applied in WSNs to carry out the data management due to similarities between WSN and P2P. With the similarities, there are differences too that makes P2P protocols inefficient in WSNs. Furthermore, to increase the efficiency and to exploit the delay tolerant nature of WSNs, where ever possible, the mobile WSNs are gaining importance. Thus, creating a three dimensional problem space to consider, i.e. mobility, WSNs and P2P. In this paper, an efficient algorithm is proposed for data management using P2P techniques for mobile WSNs. The real world implementation and deployment of proposed algorithm is also presented

  17. Generation of iPSC line iPSC-FH2.1 in hypoxic conditions from human foreskin fibroblasts

    Directory of Open Access Journals (Sweden)

    María Questa

    2016-03-01

    Full Text Available Human foreskin fibroblasts were used to generate the iPSC line iPSC-FH2.1 using the EF1a-hSTEMCCA-loxP vector expressing OCT4, SOX2, c-MYC and KLF4, in 5% O2 culture conditions. Stemness was confirmed, as was pluripotency both in vivo and in vitro, in normoxia and hypoxia. Human Embryonic Stem Cell (hESC line WA-09 and reprogrammed fibroblast primary culture HFF-FM were used as controls.

  18. FoxP2 isoforms delineate spatiotemporal transcriptional networks for vocal learning in the zebra finch

    Science.gov (United States)

    Day, Nancy F; Kimball, Todd Haswell; Aamodt, Caitlin M; Heston, Jonathan B; Hilliard, Austin T; Xiao, Xinshu; White, Stephanie A

    2018-01-01

    Human speech is one of the few examples of vocal learning among mammals yet ~half of avian species exhibit this ability. Its neurogenetic basis is largely unknown beyond a shared requirement for FoxP2 in both humans and zebra finches. We manipulated FoxP2 isoforms in Area X, a song-specific region of the avian striatopallidum analogous to human anterior striatum, during a critical period for song development. We delineate, for the first time, unique contributions of each isoform to vocal learning. Weighted gene coexpression network analysis of RNA-seq data revealed gene modules correlated to singing, learning, or vocal variability. Coexpression related to singing was found in juvenile and adult Area X whereas coexpression correlated to learning was unique to juveniles. The confluence of learning and singing coexpression in juvenile Area X may underscore molecular processes that drive vocal learning in young zebra finches and, by analogy, humans. PMID:29360038

  19. Determinants of Default in P2P Lending.

    Directory of Open Access Journals (Sweden)

    Carlos Serrano-Cinca

    Full Text Available This paper studies P2P lending and the factors explaining loan default. This is an important issue because in P2P lending individual investors bear the credit risk, instead of financial institutions, which are experts in dealing with this risk. P2P lenders suffer a severe problem of information asymmetry, because they are at a disadvantage facing the borrower. For this reason, P2P lending sites provide potential lenders with information about borrowers and their loan purpose. They also assign a grade to each loan. The empirical study is based on loans' data collected from Lending Club (N = 24,449 from 2008 to 2014 that are first analyzed by using univariate means tests and survival analysis. Factors explaining default are loan purpose, annual income, current housing situation, credit history and indebtedness. Secondly, a logistic regression model is developed to predict defaults. The grade assigned by the P2P lending site is the most predictive factor of default, but the accuracy of the model is improved by adding other information, especially the borrower's debt level.

  20. Determinants of Default in P2P Lending.

    Science.gov (United States)

    Serrano-Cinca, Carlos; Gutiérrez-Nieto, Begoña; López-Palacios, Luz

    2015-01-01

    This paper studies P2P lending and the factors explaining loan default. This is an important issue because in P2P lending individual investors bear the credit risk, instead of financial institutions, which are experts in dealing with this risk. P2P lenders suffer a severe problem of information asymmetry, because they are at a disadvantage facing the borrower. For this reason, P2P lending sites provide potential lenders with information about borrowers and their loan purpose. They also assign a grade to each loan. The empirical study is based on loans' data collected from Lending Club (N = 24,449) from 2008 to 2014 that are first analyzed by using univariate means tests and survival analysis. Factors explaining default are loan purpose, annual income, current housing situation, credit history and indebtedness. Secondly, a logistic regression model is developed to predict defaults. The grade assigned by the P2P lending site is the most predictive factor of default, but the accuracy of the model is improved by adding other information, especially the borrower's debt level.

  1. Human embryonic stem cells handbook

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2013-03-01

    Full Text Available After the Nobel prize in physiology or medicine was awarded jointly to Sir John Gurdon and Shinya Yamanaka for the discovery that mature cells can be reprogrammed to become pluripotent it became imperative to write down the review for a book entirely devoted to human embryonic stem cells (hES, those cells that are a urgent need for researchers, those cells that rekindle the ethical debates and finally, last but not least, those cells whose study paved the way to obtain induced pluripotent stem cells by the OSKC’s Yamanaka method (the OSKC acronim refers, for those not familiar with the topic, to the four stemness genes used to transfect somatic fibroblasts: Oct4, Sox2, Klf4 and c-Myc....

  2. Probing the parameters of the HAT-P-2 system

    Science.gov (United States)

    Bailey, Elizabeth; Naoz, Smadar; Batygin, Konstantin

    2018-04-01

    The HAT-P-2 system contributes an exceptional set of parameters to the exoplanetary inventory. HAT-P-2b weighs in at approximately 9 Jupiter masses, residing on one of the most eccentric, close-in orbits of any hot Jupiter (e~0.5, a~0.07). The identification of an RV trend points to the existence of an additional, long-period companion, which may have facilitated Kozai-Lidov cycles in the system over its multi-Gyr history. The well-constrained parameters of HAT-P-2b present an opportunity to predict the parameters of the perturber, and furthermore, to assess the tidal dissipation involved in the system's evolution. In this work, we employ an octupole-level secular model to account for the interaction of the two massive planets, thus classifying the system's deviations away from purely quadrupolar dynamics.

  3. Mobile P2P Web Services Using SIP

    Directory of Open Access Journals (Sweden)

    Guido Gehlen

    2007-01-01

    Full Text Available Telecommunication networks and the Internet are growing together. Peer-to-Peer (P2P services which are originally offered by network providers, like telephony and messaging, are provided through VoIP and Instant Messaging (IM by Internet service providers, too. The IP Multimedia Subsystem (IMS is the answer of the telecommunication industry to this trend and aims at providing Internet P2P and multimedia services controlled by the network operators. The IMS provides mobility and session management as well as message routing, security, and billing.

  4. DA-6034-induced mucin secretion via Ca2+-dependent pathways through P2Y receptor stimulation.

    Science.gov (United States)

    Lee, Hun; Kim, Eung Kweon; Kim, Ji Yeon; Yang, Yu-Mi; Shin, Dong Min; Kang, Kyung Koo; Kim, Tae-im

    2014-09-11

    We evaluated whether DA-6034 is involved in mucin secretion via P2Y receptor activation and/or intracellular Ca2+ concentration ([Ca2+]i) change. Also, we investigated the effect of P2Y receptor inhibitors or Ca2+ chelators on the DA-6034-induced mucin secretion and [Ca2+]i increases. Effects of DA-6034 on mucin expression in primary, cultured, conjunctival epithelial cells was studied using RT-PCR, Western blot analysis, and periodic acid-schiff (PAS) staining. To evaluate thin film layer thickness generated by mucin and fluid secretion, cells were incubated in DA-6034 with/without P2Y antagonists or extracellular/intracellular Ca2+ chelators, and were imaged with confocal microscope using Texas Red-dextran dye. In addition, DA-6034-induced Ca2+-dependent Cl- channels opening was evaluated using perforated patch clamp. Fluo-4/AM was used to measure changes in [Ca2+]i induced by DA-6034 in Ca2+-free or Ca2+-containing buffered condition, as well as P2Y antagonists. DA-6034 induced the expression of mucin genes, production of mucin protein, and increase of number of mucin-secreting cells. P2Y antagonists inhibited DA-6034-induced mucin and fluid secretion, which was also affected by extracellular/intracellular Ca2+ chelators. DA-6034 stimulated Cl- channel opening and [Ca2+]i elevation. Further, [Ca2+]i increases induced by DA-6034 were lacking in either P2Y antagonists or Ca2+-free buffered condition, and diminished when endoplasmic reticulum Ca2+ was depleted by cyclopiazonic acid in Ca2+-free buffered condition. This study demonstrated that DA-6034 has a potential to induce mucin secretion via Ca2+-dependent pathways through P2Y receptors in multilayer, cultured, human conjunctival epithelial cells. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  5. Antidepressants inhibit P2X4 receptor function: a possible involvement in neuropathic pain relief

    Directory of Open Access Journals (Sweden)

    Tozaki-Saitoh Hidetoshi

    2009-04-01

    Full Text Available Abstract Background Neuropathic pain is characterized by pain hypersensitivity to innocuous stimuli (tactile allodynia that is nearly always resistant to known treatments such as non-steroidal anti-inflammatory drugs or even opioids. It has been reported that some antidepressants are effective for treating neuropathic pain. However, the underlying molecular mechanisms are not well understood. We have recently demonstrated that blocking P2X4 receptors in the spinal cord reverses tactile allodynia after peripheral nerve injury in rats, implying that P2X4 receptors are a key molecule in neuropathic pain. We investigated a possible role of antidepressants as inhibitors of P2X4 receptors and analysed their analgesic mechanism using an animal model of neuropathic pain. Results Antidepressants strongly inhibited ATP-mediated Ca2+ responses in P2X4 receptor-expressing 1321N1 cells, which are known to have no endogenous ATP receptors. Paroxetine exhibited the most powerful inhibition of calcium influx via rat and human P2X4 receptors, with IC50 values of 2.45 μM and 1.87 μM, respectively. Intrathecal administration of paroxetine produced a striking antiallodynic effect in an animal model of neuropathic pain. Co-administration of WAY100635, ketanserin or ondansetron with paroxetine induced no significant change in the antiallodynic effect of paroxetine. Furthermore, the antiallodynic effect of paroxetine was observed even in rats that had received intrathecal pretreatment with 5,7-dihydroxytryptamine, which dramatically depletes spinal 5-hydroxytryptamine. Conclusion These results suggest that paroxetine acts as a potent analgesic in the spinal cord via a mechanism independent of its inhibitory effect on serotonin transporters. Powerful inhibition on P2X4 receptors may underlie the analgesic effect of paroxetine, and it is possible that some antidepressants clinically used in patients with neuropathic pain show antiallodynic effects, at least in part

  6. Association of P2X7 receptor polymorphisms with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

    DEFF Research Database (Denmark)

    Wesselius, A; Bours, M J L; Henriksen, Z

    2013-01-01

    The P2X(7) receptor is thought to be involved in bone physiology in a pro-osteogenic manner. Therefore, we examined associations between genetic variations in the P2X(7) receptor gene and bone mineral density (BMD). We found an association between four non-synonymous polymorphism of the human P2X...

  7. Arrestin scaffolds NHERF1 to the P2Y12 receptor to regulate receptor internalization.

    Science.gov (United States)

    Nisar, Shaista P; Cunningham, Margaret; Saxena, Kunal; Pope, Robert J; Kelly, Eamonn; Mundell, Stuart J

    2012-07-13

    We have recently shown in a patient with mild bleeding that the PDZ-binding motif of the platelet G protein-coupled P2Y(12) receptor (P2Y(12)R) is required for effective receptor traffic in human platelets. In this study we show for the first time that the PDZ motif-binding protein NHERF1 exerts a major role in potentiating G protein-coupled receptor (GPCR) internalization. NHERF1 interacts with the C-tail of the P2Y(12)R and unlike many other GPCRs, NHERF1 interaction is required for effective P2Y(12)R internalization. In vitro and prior to agonist stimulation P2Y(12)R/NHERF1 interaction requires the intact PDZ binding motif of this receptor. Interestingly on receptor stimulation NHERF1 no longer interacts directly with the receptor but instead binds to the receptor via the endocytic scaffolding protein arrestin. These findings suggest a novel model by which arrestin can serve as an adaptor to promote NHERF1 interaction with a GPCR to facilitate effective NHERF1-dependent receptor internalization.

  8. P2X receptor channels in endocrine glands

    Czech Academy of Sciences Publication Activity Database

    Stojilkovic, S. S.; Zemková, Hana

    2013-01-01

    Roč. 2, č. 4 (2013), s. 173-180 ISSN 2190-460X R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : ATP * purinergic P2X receptor channels * pituitary * endocrine glands Subject RIV: ED - Physiology

  9. The P2P approach to interorganizational workflows

    NARCIS (Netherlands)

    Aalst, van der W.M.P.; Weske, M.H.; Dittrich, K.R.; Geppert, A.; Norrie, M.C.

    2001-01-01

    This paper describes in an informal way the Public-To-Private (P2P) approach to interorganizational workflows, which is based on a notion of inheritance. The approach consists of three steps: (1) create a common understanding of the interorganizational workflow by specifying a shared public

  10. Measurement and Analysis of P2P IPTV Program Resource

    Directory of Open Access Journals (Sweden)

    Wenxian Wang

    2014-01-01

    Full Text Available With the rapid development of P2P technology, P2P IPTV applications have received more and more attention. And program resource distribution is very important to P2P IPTV applications. In order to collect IPTV program resources, a distributed multi-protocol crawler is proposed. And the crawler has collected more than 13 million pieces of information of IPTV programs from 2009 to 2012. In addition, the distribution of IPTV programs is independent and incompact, resulting in chaos of program names, which obstructs searching and organizing programs. Thus, we focus on characteristic analysis of program resources, including the distributions of length of program names, the entropy of the character types, and hierarchy depth of programs. These analyses reveal the disorderly naming conventions of P2P IPTV programs. The analysis results can help to purify and extract useful information from chaotic names for better retrieval and accelerate automatic sorting of program and establishment of IPTV repository. In order to represent popularity of programs and to predict user behavior and popularity of hot programs over a period, we also put forward an analytical model of hot programs.

  11. Measurement and analysis of P2P IPTV program resource.

    Science.gov (United States)

    Wang, Wenxian; Chen, Xingshu; Wang, Haizhou; Zhang, Qi; Wang, Cheng

    2014-01-01

    With the rapid development of P2P technology, P2P IPTV applications have received more and more attention. And program resource distribution is very important to P2P IPTV applications. In order to collect IPTV program resources, a distributed multi-protocol crawler is proposed. And the crawler has collected more than 13 million pieces of information of IPTV programs from 2009 to 2012. In addition, the distribution of IPTV programs is independent and incompact, resulting in chaos of program names, which obstructs searching and organizing programs. Thus, we focus on characteristic analysis of program resources, including the distributions of length of program names, the entropy of the character types, and hierarchy depth of programs. These analyses reveal the disorderly naming conventions of P2P IPTV programs. The analysis results can help to purify and extract useful information from chaotic names for better retrieval and accelerate automatic sorting of program and establishment of IPTV repository. In order to represent popularity of programs and to predict user behavior and popularity of hot programs over a period, we also put forward an analytical model of hot programs.

  12. Comparing Pedophile Activity in Different P2P Systems

    Directory of Open Access Journals (Sweden)

    Raphaël Fournier

    2014-07-01

    Full Text Available Peer-to-peer (P2P systems are widely used to exchange content over the Internet. Knowledge of pedophile activity in such networks remains limited, despite having important social consequences. Moreover, though there are different P2P systems in use, previous academic works on this topic focused on one system at a time and their results are not directly comparable. We design a methodology for comparing KAD and eDonkey, two P2P systems among the most prominent ones and with different anonymity levels. We monitor two eDonkey servers and the KAD network during several days and record hundreds of thousands of keyword-based queries. We detect pedophile-related queries with a previously validated tool and we propose, for the first time, a large-scale comparison of pedophile activity in two different P2P systems. We conclude that there are significantly fewer pedophile queries in KAD than in eDonkey (approximately 0.09% vs. 0.25%.

  13. P2X(3) receptor gating near normal body temperature

    Czech Academy of Sciences Publication Activity Database

    Kmyhz, V.; Maximyuk, O.; Teslenko, V.; Verkhratsky, Alexei; Krishtal, O.

    2008-01-01

    Roč. 456, č. 12 (2008), s. 339-347 ISSN 0031-6768 Institutional research plan: CEZ:AV0Z50390703 Keywords : P2X3 receptors * Temperature-sensitivity * Gating Subject RIV: FH - Neurology Impact factor: 3.526, year: 2008

  14. Pollution Prevention Successes Database (P2SDb) user guide

    International Nuclear Information System (INIS)

    1995-07-01

    When Pollution Prevention Opportunity Assessments (P2OAs) were launched at the Hanford Site during the summer of 1994, the first comment received from those using them expressed the desire for a method to report assessments electronically. As a temporary measure, macros were developed for use on word processing systems, but a more formal database was obviously needed. Additionally, increased DOE and Washington state reporting requirements for pollution prevention suggested that a database system would streamline the reporting process. The Pollution Prevention Group of Westinghouse Hanford Company (WHC) contracted with the Data Automation Engineering Department from ICF Kaiser Hanford Company (ICFKH) to develop the system. The scope was to develop a database that will track P2OAs conducted by the facilities and contractors at the Hanford Site. It will also track pollution prevention accomplishments that are not the result of P2OAs and document a portion of the Process Waste Assessments conducted in the past. To accommodate the above criteria, yet complete the system in a timely manner, the Pollution Prevention Successes Database (P2SDb) is being implemented in three phases. The first phase will automate the worksheets to provide both input and output of the data associated with the worksheets. The second phase will automate standard summary reports and ad hoc reports. The third phase will provide automated searching of the database to facilitate the sharing of pollution prevention experiences among various users. This User's Guide addresses only the Phase 1 system

  15. Evidence for requirement of tyrosine phosphorylation in endothelial P2Y- and P2U- purinoceptor stimulation of prostacyclin release.

    Science.gov (United States)

    Bowden, A.; Patel, V.; Brown, C.; Boarder, M. R.

    1995-01-01

    1. The release of prostacyclin (PGI2) from vascular endothelial cells is stimulated by ATP acting at G protein-coupled P2-purinoceptors. Here we investigate the hypothesis that tyrosine protein phosphorylations are involved in this response. 2. The use of Western blots with anti-phosphotyrosine antibodies showed that 30 microM 2MeSATP (selective for P2Y-purinoceptors), 300 microM UTP (selective for P2U-purinoceptors) and 300 microM ATP (effective at both these purinoceptors), each stimulate the tyrosine phosphorylation of proteins in bovine cultured aortic endothelial cells. Each of these agonists also stimulates 6-keto PGF1 alpha accumulation in the medium (an index of PGI2 release) in these cells in the same period. 3. The tyrosine kinase inhibitor, genistein, inhibits the 6-keto PGF1 alpha response with the same concentration-dependency (1-100 microM) as the tyrosine phosphorylation response. 4. Tyrphostin, a structurally and functionally distinct tyrosine kinase inhibitor, is also a potent inhibitor (0.1-10 microM) of the 6-keto PGF1 alpha response. 5. Neither tyrphostin nor genistein inhibit the phospholipase C response to P2-purinoceptor stimulation. Furthermore, these inhibitors do not affect the 6-keto PGF1 alpha response to ionomycin. 6. These results show that the regulation of vascular endothelial cells by ATP acting at both P2Y- and P2U-purinoceptors involves the stimulation of tyrosine phosphorylation, and suggest that this is a necessary event for the purinoceptor-mediated stimulation of PGI2 production. Images Figure 1 Figure 5 PMID:8590971

  16. Adenine Nucleotide Analogues Locked in a Northern Methanocarba Conformation: Enhanced Stability and Potency as P2Y1 Receptor Agonists

    Science.gov (United States)

    Ravi, R. Gnana; Kim, Hak Sung; Servos, Jörg; Zimmermann, Herbert; Lee, Kyeong; Maddileti, Savitri; Boyer, José L.; Harden, T. Kendall; Jacobson, Kenneth A.

    2016-01-01

    Preference for the Northern (N) ring conformation of the ribose moiety of nucleotide 5′-triphosphate agonists at P2Y1, P2Y2, P2Y4, and P2Y11 receptors, but not P2Y6 receptors, was established using a ring-constrained methanocarba (a 3.1.0-bicyclohexane) ring as a ribose substitute (Kim et al. J. Med. Chem. 2002, 45, 208–218.). We have now combined the ring-constrained (N)-methanocarba modification of adenine nucleotides with other functionalities known to enhance potency at P2 receptors. The potency of the newly synthesized analogues was determined in the stimulation of phospholipase C through activation of turkey erythrocyte P2Y1 or human P2Y1 and P2Y2 receptors stably expressed in astrocytoma cells. An (N)-methanocarba-2-methylthio-ADP analogue displayed an EC50 at the hP2Y1 receptor of 0.40 nM and was 55-fold more potent than the corresponding triphosphate and 16-fold more potent than the riboside 5′-diphosphate. 2-Cl–(N)-methanocarba-ATP and its N6-Me analogue were also highly selective, full agonists at P2Y1 receptors. The (N)-methanocarba-2-methylthio and 2-chloromonophosphate analogues were full agonists exhibiting micromolar potency at P2Y1 receptors, while the corresponding ribosides were inactive. Although β,γ-methylene-ATP was inactive at P2Y receptors, β,γ-methylene-(N)-methanocarba-ATP was a potent hP2Y1 receptor agonist with an EC50 of 160 nM and was selective versus hP2Y2 and hP2Y4 receptors. The rates of hydrolysis of Northern (N) and Southern (S) methanocarba analogues of AMP by rat 5′-ectonucleotidase were negligible. The rates of hydrolysis of the corresponding triphosphates by recombinant rat NTPDase1 and 2 were studied. Both isomers were hydrolyzed by NTPDase 1 at about half the rate of ATP hydrolysis. The (N) isomer was hardly hydrolyzed by NTPDase 2, while the (S) isomer was hydrolyzed at one-third of the rate of ATP hydrolysis. This suggests that new, more stable and selective nucleotide agonists may be designed on the basis of

  17. Autocrine Regulation of UVA-Induced IL-6 Production via Release of ATP and Activation of P2Y Receptors

    Science.gov (United States)

    Kawano, Ayumi; Kadomatsu, Remi; Ono, Miyu; Kojima, Shuji; Tsukimoto, Mitsutoshi; Sakamoto, Hikaru

    2015-01-01

    Extracellular nucleotides, such as ATP, are released from cells in response to various stimuli and act as intercellular signaling molecules through activation of P2 receptors. Exposure to the ultraviolet radiation A (UVA) component of sunlight causes molecular and cellular damage, and in this study, we investigated the involvement of extracellular nucleotides and P2 receptors in the UVA-induced cellular response. Human keratinocyte-derived HaCaT cells were irradiated with a single dose of UVA (2.5 J/cm2), and ATP release and interleukin (IL)-6 production were measured. ATP was released from cells in response to UVA irradiation, and the release was blocked by pretreatment with inhibitors of gap junction hemichannels or P2X7 receptor antagonist. IL-6 production was increased after UVA irradiation, and this increase was inhibited by ecto-nucleotidase or by antagonists of P2Y11 or P2Y13 receptor. These results suggest that UVA-induced IL-6 production is mediated by release of ATP through hemichannels and P2X7 receptor, followed by activation of P2Y11 and P2Y13 receptors. Interestingly, P2Y11 and P2Y13 were associated with the same pattern of IL-6 production, though they trigger different intracellular signaling cascades: Ca2+-dependent and PI3K-dependent, respectively. Thus, IL-6 production in response to UVA-induced ATP release involves at least two distinct pathways, mediated by activation of P2Y11 and P2Y13 receptors. PMID:26030257

  18. Impaired P2X1 Receptor-Mediated Adhesion in Eosinophils from Asthmatic Patients.

    Science.gov (United States)

    Wright, Adam; Mahaut-Smith, Martyn; Symon, Fiona; Sylvius, Nicolas; Ran, Shaun; Bafadhel, Mona; Muessel, Michelle; Bradding, Peter; Wardlaw, Andrew; Vial, Catherine

    2016-06-15

    Eosinophils play an important role in the pathogenesis of asthma and can be activated by extracellular nucleotides released following cell damage or inflammation. For example, increased ATP concentrations were reported in bronchoalveolar lavage fluids of asthmatic patients. Although eosinophils are known to express several subtypes of P2 receptors for extracellular nucleotides, their function and contribution to asthma remain unclear. In this article, we show that transcripts for P2X1, P2X4, and P2X5 receptors were expressed in healthy and asthmatic eosinophils. The P2X receptor agonist α,β-methylene ATP (α,β-meATP; 10 μM) evoked rapidly activating and desensitizing inward currents (peak 18 ± 3 pA/pF at -60 mV) in healthy eosinophils, typical of P2X1 homomeric receptors, which were abolished by the selective P2X1 antagonist NF449 (1 μM) (3 ± 2 pA/pF). α,β-meATP-evoked currents were smaller in eosinophils from asthmatic patients (8 ± 2 versus 27 ± 5 pA/pF for healthy) but were enhanced following treatment with a high concentration of the nucleotidase apyrase (17 ± 5 pA/pF for 10 IU/ml and 11 ± 3 pA/pF for 0.32 IU/ml), indicating that the channels are partially desensitized by extracellular nucleotides. α,β-meATP (10 μM) increased the expression of CD11b activated form in eosinophils from healthy, but not asthmatic, donors (143 ± 21% and 108 ± 11% of control response, respectively). Furthermore, α,β-meATP increased healthy (18 ± 2% compared with control 10 ± 1%) but not asthmatic (13 ± 1% versus 10 ± 0% for control) eosinophil adhesion. Healthy human eosinophils express functional P2X1 receptors whose activation leads to eosinophil αMβ2 integrin-dependent adhesion. P2X1 responses are constitutively reduced in asthmatic compared with healthy eosinophils, probably as the result of an increase in extracellular nucleotide concentration. Copyright © 2016 by The American Association of Immunologists, Inc.

  19. The cancer-promoting gene fatty acid-binding protein 5 (FABP5) is epigenetically regulated during human prostate carcinogenesis.

    Science.gov (United States)

    Kawaguchi, Koichiro; Kinameri, Ayumi; Suzuki, Shunsuke; Senga, Shogo; Ke, Youqiang; Fujii, Hiroshi

    2016-02-15

    FABPs (fatty-acid-binding proteins) are a family of low-molecular-mass intracellular lipid-binding proteins consisting of ten isoforms. FABPs are involved in binding and storing hydrophobic ligands such as long-chain fatty acids, as well as transporting these ligands to the appropriate compartments in the cell. FABP5 is overexpressed in multiple types of tumours. Furthermore, up-regulation of FABP5 is strongly associated with poor survival in triple-negative breast cancer. However, the mechanisms underlying the specific up-regulation of the FABP5 gene in these cancers remain poorly characterized. In the present study, we determined that FABP5 has a typical CpG island around its promoter region. The DNA methylation status of the CpG island in the FABP5 promoter of benign prostate cells (PNT2), prostate cancer cells (PC-3, DU-145, 22Rv1 and LNCaP) and human normal or tumour tissue was assessed by bisulfite sequencing analysis, and then confirmed by COBRA (combined bisulfite restriction analysis) and qAMP (quantitative analysis of DNA methylation using real-time PCR). These results demonstrated that overexpression of FABP5 in prostate cancer cells can be attributed to hypomethylation of the CpG island in its promoter region, along with up-regulation of the direct trans-acting factors Sp1 (specificity protein 1) and c-Myc. Together, these mechanisms result in the transcriptional activation of FABP5 expression during human prostate carcinogenesis. Importantly, silencing of Sp1, c-Myc or FABP5 expression led to a significant decrease in cell proliferation, indicating that up-regulation of FABP5 expression by Sp1 and c-Myc is critical for the proliferation of prostate cancer cells. © 2016 Authors; published by Portland Press Limited.

  20. Supporting seamless mobility for P2P live streaming.

    Science.gov (United States)

    Kim, Eunsam; Kim, Sangjin; Lee, Choonhwa

    2014-01-01

    With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme.

  1. Supporting Seamless Mobility for P2P Live Streaming

    Directory of Open Access Journals (Sweden)

    Eunsam Kim

    2014-01-01

    Full Text Available With advent of various mobile devices with powerful networking and computing capabilities, the users' demand to enjoy live video streaming services such as IPTV with mobile devices has been increasing rapidly. However, it is challenging to get over the degradation of service quality due to data loss caused by the handover. Although many handover schemes were proposed at protocol layers below the application layer, they inherently suffer from data loss while the network is being disconnected during the handover. We therefore propose an efficient application-layer handover scheme to support seamless mobility for P2P live streaming. By simulation experiments, we show that the P2P live streaming system with our proposed handover scheme can improve the playback continuity significantly compared to that without our scheme.

  2. Energetic band structure of Zn3P2 crystals

    Science.gov (United States)

    Stamov, I. G.; Syrbu, N. N.; Dorogan, A. V.

    2013-01-01

    Optical functions n, k, ε1, ε2 and d2ε2/dE2 have been determined from experimental reflection spectra in the region of 1-10 eV. The revealed electronic transitions are localized in the Brillouin zone. The magnitude of valence band splitting caused by the spin-orbital interaction ΔSO is lower than the splitting caused by the crystal field ΔCR in the center of Brillouin zone and L and X points. The switching effects are investigated in Zn3P2 crystals. The characteristics of experimental samples with electric switching, adjustable resistors, and time relays based on Zn3P2 are presented.

  3. Towards secure mobile P2P applications using JXME

    OpenAIRE

    Domingo Prieto, Marc; Prieto Blázquez, Josep; Herrera Joancomartí, Jordi; Arnedo Moreno, Joan

    2014-01-01

    Mobile devices have become ubiquitous, allowing the integration of new information from a large range of devices. However, the development of new applications requires a powerful framework which simplifies their construction. JXME is the JXTA implementation for mobile devices using J2ME, its main value being its simplicity when creating peer-to-peer (P2P) applications on limited devices. On that regard, an issue that is becoming very important in the recent times is being able to provide ...

  4. Pemetaan Pusat Pelayanan Terpadu Pemberdayaan Perempuan dan Anak (P2TP2A Provinsi Sumatera Bar

    Directory of Open Access Journals (Sweden)

    Hallen Abu Bakar

    2017-09-01

    Full Text Available The Center of Integrated Service for Women and Children Empowerment (P2TP2A is established by the government based community in order to eliminate the violence towards women and children. It also aims to empower the position of women and children. The purpose of the study is to describe comprehensively the existance of P2TP2A in sub-district, district, city, and province in West Sumatra. Descriptive qualitative research was used where the data taken from questionnaire and in-deepthinterview. The study found that the Center of Integrated Service for Women and Children Empowerment was established by following certain procedure, legality and personnel structure. It also found that the majority of P2TP2A in West Sumatra has insufficient infrastructures. Meanwhile, it is only P2TP2A Limpapeh Rumah Nan Gadang of West Sumatera, and P2TP2A Luhak Nan Tuo Batusangkar has sufficient infrastructures. Many of them were located at the corner of Community Empowerment and Women and Family Planning office (BPMPKB. Every P2TP2A in those district and city have made their programs, but they faced some difficulties in realize them doe to financial problems. The human resources were recruited from SKPD, academician, professional, society figures, LSM who concern on gender meanstreaming. They play the role more on providing the service than giving information and empowerment. The last finding of the study showed that the involvement of local government, Health offices, social services, police, ministry of religion, prosecutors and social services have been effective.

  5. An unusual methylene aziridine refined in P2(1)/c and the nonstandard setting P2(1)/n.

    Science.gov (United States)

    Feast, George C; Haestier, James; Page, Lee W; Robertson, Jeremy; Thompson, Amber L; Watkin, David J

    2009-12-01

    The unusual methylene aziridine 6-tert-butyl-3-oxa-2-thia-1-azabicyclo[5.1.0]oct-6-ene 2,2-dioxide, C(9)H(15)NO(3)S, was found to crystallize with two molecules in the asymmetric unit. The structure was solved in both the approximately orthogonal and the oblique settings of space group No. 14, viz. P2(1)/n and P2(1)/c, respectively. A comparison of these results clearly displayed an increase in the correlation between coordinates in the ac plane for the oblique cell. The increase in the corresponding covariances makes a significant contribution to the standard uncertainties of derived parameters, e.g. bond lengths. Since there is yet no CIF definition for the full variance-covariance matrix, there are clear advantages to reporting the structure in the nonstandard space-group setting.

  6. Structural basis for subtype-specific inhibition of the P2X7 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Karasawa, Akira; Kawate, Toshimitsu (Cornell)

    2016-12-09

    The P2X7 receptor is a non-selective cation channel activated by extracellular adenosine triphosphate (ATP). Chronic activation of P2X7 underlies many health problems such as pathologic pain, yet we lack effective antagonists due to poorly understood mechanisms of inhibition. Here we present crystal structures of a mammalian P2X7 receptor complexed with five structurally-unrelated antagonists. Unexpectedly, these drugs all bind to an allosteric site distinct from the ATP-binding pocket in a groove formed between two neighboring subunits. This novel drug-binding pocket accommodates a diversity of small molecules mainly through hydrophobic interactions. Functional assays propose that these compounds allosterically prevent narrowing of the drug-binding pocket and the turret-like architecture during channel opening, which is consistent with a site of action distal to the ATP-binding pocket. These novel mechanistic insights will facilitate the development of P2X7-specific drugs for treating human diseases.

  7. Final Design of the SLAC P2 Marx Klystron Modulator

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, M.A.; Benwell, A.; Burkhart, C.; Larsen, R.; MacNair, D.; Nguyen, M.; Olsen, J.; /SLAC

    2011-11-08

    The SLAC P2 Marx has been under development for two years, and follows on the P1 Marx as an alternative to the baseline klystron modulator for the International Linear Collider. The P2 Marx utilizes a redundant architecture, air-insulation, a control system with abundant diagnostic access, and a novel nested droop correction scheme. This paper is an overview of the design of this modulator. There are several points of emphasis for the P2 Marx design. First, the modulator must be compatible with the ILC two-tunnel design. In this scheme, the modulator and klystron are located within a service tunnel with limited access and available footprint for a modulator. Access to the modulator is only practical from one side. Second, the modulator must have high availability. Robust components are not sufficient alone to achieve availability much higher than 99%. Therefore, redundant architectures are necessary. Third, the modulator must be relatively low cost. Because of the large number of stations in the ILC, the investment needed for the modulator components is significant. High-volume construction techniques which take advantage of an economy of scale must be utilized. Fourth, the modulator must be simple and efficient to maintain. If a modulator does become inoperable, the MTTR must be small. Fifth, even though the present application for the modulator is for the ILC, future accelerators can also take advantage of this development effort. The hardware, software, and concepts developed in this project should be designed such that further development time necessary for other applications is minimal.

  8. Detecting P2P Botnet in Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Shang-Chiuan Su

    2018-01-01

    Full Text Available Software Defined Network separates the control plane from network equipment and has great advantage in network management as compared with traditional approaches. With this paradigm, the security issues persist to exist and could become even worse because of the flexibility on handling the packets. In this paper we propose an effective framework by integrating SDN and machine learning to detect and categorize P2P network traffics. This work provides experimental evidence showing that our approach can automatically analyze network traffic and flexibly change flow entries in OpenFlow switches through the SDN controller. This can effectively help the network administrators manage related security problems.

  9. Functional interaction between type III-secreted protein IncA of Chlamydophila psittaci and human G3BP1.

    Science.gov (United States)

    Borth, Nicole; Litsche, Katrin; Franke, Claudia; Sachse, Konrad; Saluz, Hans Peter; Hänel, Frank

    2011-01-31

    Chlamydophila (Cp.) psittaci, the causative agent of psittacosis in birds and humans, is the most important zoonotic pathogen of the family Chlamydiaceae. These obligate intracellular bacteria are distinguished by a unique biphasic developmental cycle, which includes proliferation in a membrane-bound compartment termed inclusion. All Chlamydiaceae spp. possess a coding capacity for core components of a Type III secretion apparatus, which mediates specific delivery of anti-host effector proteins either into the chlamydial inclusion membrane or into the cytoplasm of target eukaryotic cells. Here we describe the interaction between Type III-secreted protein IncA of Cp. psittaci and host protein G3BP1 in a yeast two-hybrid system. In GST-pull down and co-immunoprecipitation experiments both in vitro and in vivo interaction between full-length IncA and G3BP1 were shown. Using fluorescence microscopy, the localization of G3BP1 near the inclusion membrane of Cp. psittaci-infected Hep-2 cells was demonstrated. Notably, infection of Hep-2 cells with Cp. psittaci and overexpression of IncA in HEK293 cells led to a decrease in c-Myc protein concentration. This effect could be ascribed to the interaction between IncA and G3BP1 since overexpression of an IncA mutant construct disabled to interact with G3BP1 failed to reduce c-Myc concentration. We hypothesize that lowering the host cell c-Myc protein concentration may be part of a strategy employed by Cp. psittaci to avoid apoptosis and scale down host cell proliferation.

  10. P2X7 receptors in satellite glial cells mediate high functional expression of P2X3 receptors in immature dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Chen Yong

    2012-02-01

    Full Text Available Abstract Background The purinergic P2X3 receptor (P2X3R expressed in the dorsal root ganglion (DRG sensory neuron and the P2X7 receptor (P2X7R expressed in the surrounding satellite glial cell (SGC are two major receptors participating in neuron-SGC communication in adult DRGs. Activation of P2X7Rs was found to tonically reduce the expression of P2X3Rs in DRGs, thus inhibiting the abnormal pain behaviors in adult rats. P2X receptors are also actively involved in sensory signaling in developing rodents. However, very little is known about the developmental change of P2X7Rs in DRGs and the interaction between P2X7Rs and P2X3Rs in those animals. We therefore examined the expression of P2X3Rs and P2X7Rs in postnatal rats and determined if P2X7R-P2X3R control exists in developing rats. Findings We immunostained DRGs of immature rats and found that P2X3Rs were expressed only in neurons and P2X7Rs were expressed only in SGCs. Western blot analyses indicated that P2X3R expression decreased while P2X7R expression increased with the age of rats. Electrophysiological studies showed that the number of DRG neurons responding to the stimulation of the P2XR agonist, α,β-meATP, was higher and the amplitudes of α,β-meATP-induced depolarizations were larger in immature DRG neurons. As a result, P2X3R-mediated flinching responses were much more pronounced in immature rats than those found in adult rats. When we reduced P2X7R expression with P2X7R-siRNA in postnatal and adult rats, P2X3R-mediated flinch responses were greatly enhanced in both rat populations. Conclusions These results show that the P2X7R expression increases as rats age. In addition, P2X7Rs in SGCs exert inhibitory control on the P2X3R expression and function in sensory neurons of immature rats, just as observed in adult rats. Regulation of P2X7R expression is likely an effective way to control P2X3R activity and manage pain relief in infants.

  11. Parameterization-based tracking for the P2 experiment

    Science.gov (United States)

    Sorokin, Iurii

    2017-08-01

    The P2 experiment in Mainz aims to determine the weak mixing angle θW at low momentum transfer by measuring the parity-violating asymmetry of elastic electronproton scattering. In order to achieve the intended precision of Δ(sin2 θW)/sin2θW = 0:13% within the planned 10 000 hours of running the experiment has to operate at the rate of 1011 detected electrons per second. Although it is not required to measure the kinematic parameters of each individual electron, every attempt is made to achieve the highest possible throughput in the track reconstruction chain. In the present work a parameterization-based track reconstruction method is described. It is a variation of track following, where the results of the computation-heavy steps, namely the propagation of a track to the further detector plane, and the fitting, are pre-calculated, and expressed in terms of parametric analytic functions. This makes the algorithm extremely fast, and well-suited for an implementation on an FPGA. The method also takes implicitly into account the actual phase space distribution of the tracks already at the stage of candidate construction. Compared to a simple algorithm, that does not use such information, this allows reducing the combinatorial background by many orders of magnitude, down to O(1) background candidate per one signal track. The method is developed specifically for the P2 experiment in Mainz, and the presented implementation is tightly coupled to the experimental conditions.

  12. Parameterization-based tracking for the P2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sorokin, Iurii [Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany); Collaboration: P2-Collaboration

    2016-07-01

    The P2 experiment at the new MESA accelerator in Mainz aims to determine the weak mixing angle by measuring the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. To achieve an unprecedented precision an order of 10{sup 11} scattered electrons per second have to be acquired. %within the acceptance. Whereas the tracking system is not required to operate at such high rates, every attempt is made to achieve as high rate capability as possible. The P2 tracking system will consist of four planes of high-voltage monolithic active pixel sensors (HV-MAPS). With the present preliminary design one expects about 150 signal electron tracks and 20000 background hits (from bremsstrahlung photons) per plane in every 50 ns readout frame at the full rate. In order to cope with this extreme combinatorial background in on-line mode, a parameterization-based tracking is considered as a possible solution. The idea is to transform the hit positions into a set of weakly correlated quantities, and to find simple (e.g. polynomial) functions of these quantities, that would give the required characteristics of the track (e.g. momentum). The parameters of the functions are determined from a sample of high-quality tracks, taken either from a simulation, or reconstructed in a conventional way from a sample of low-rate data.

  13. Fundamental absorption edge of CdP2 single crystals

    International Nuclear Information System (INIS)

    Bondar', G.I.; Koval', V.S.; Kurik, M.V.

    1986-01-01

    Fundamental absorption edge of tetragonal CdP 2 crystals is investigated within the temperature range of 4.2-293 K. The crystals are grown by the Bridgman methods and resublimation methods and possess different degree of perfection and purity. In perfect CdP 2 crystals with small concentration of impurities in the region of K > 20 cm -1 the shape of the absorption edge spectrum is described by the Urbach rule. The Urbach rule parameters are defined. The electron-phonon interaction is shown to be the determinant at K > 20 cm -1 and the direct vertical transition is observed. A slight additional absorption with maximum at 2.163 eV within the range of K -1 and at T ≤ 50 is associated with transition from shallow acceptor level to the conduction zone. The impurity leads to the shift of the fundamental absorption edge to the long-wavelength side and diffusion of electrons on impurities is resulted

  14. Is the auditory evoked P2 response a biomarker of learning?

    Directory of Open Access Journals (Sweden)

    Kelly eTremblay

    2014-02-01

    Full Text Available Even though auditory training exercises for humans have been shown to improve certain perceptual skills of individuals with and without hearing loss, there is a lack of knowledge pertaining to which aspects of training are responsible for the perceptual gains, and which aspects of perception are changed. To better define how auditory training impacts brain and behavior, electroencephalography and magnetoencephalography have been used to determine the time course and coincidence of cortical modulations associated with different types of training. Here we focus on P1-N1-P2 auditory evoked responses (AEP, as there are consistent reports of gains in P2 amplitude following various types of auditory training experiences; including music and speech-sound training. The purpose of this experiment was to determine if the auditory evoked P2 response is a biomarker of learning. To do this, we taught native English speakers to identify a new pre-voiced temporal cue that is not used phonemically in the English language so that coinciding changes in evoked neural activity could be characterized. To differentiate possible effects of repeated stimulus exposure and a button-pushing task from learning itself, we examined modulations in brain activity in a group of participants who learned to identify the pre-voicing contrast and compared it to participants, matched in time, and stimulus exposure, that did not. The main finding was that the amplitude of the P2 auditory evoked response increased across repeated EEG sessions for all groups, regardless of any change in perceptual performance. What’s more, these effects were retained for months. Changes in P2 amplitude were attributed to changes in neural activity associated with the acquisition process and not the learned outcome itself. A further finding was the expression of a late negativity (LN wave 600-900 ms post-stimulus onset, post-training, exclusively for the group that learned to identify the pre

  15. Deletion of P2X2 and P2X3 receptor subunits does not alter motility of the mouse colon

    Directory of Open Access Journals (Sweden)

    Matthew DeVries

    2010-03-01

    Full Text Available Purinergic P2X receptors contribute to neurotransmission in the gut. P2X receptors are ligand-gated cation channels that mediate synaptic excitation in subsets of enteric neurons. The present study evaluated colonic motility in vitro and in vivo in wild type (WT and P2X2 and P2X3 subunit knockout (KO mice. The muscarinic receptor agonist, bethanechol (0.3-3 micromolar, caused similar contractions of the longitudinal muscle in colon segments from WT, P2X2 and P2X3 subunit KO mice. Nicotine (1-300 micromolar, acting at neuronal nicotinic receptors, caused similar longitudinal muscle relaxations in colonic segments from WT and P2X2 and P2X3 subunit KO mice. Nicotine-induced relaxations were inhibited by nitro-L-arginine (NLA, 100 micromolar and apamin (0.1 micromolar which block inhibitory neuromuscular transmission. ATP (1-1000 micromolar caused contractions only in the presence of NLA and apamin. ATP-induced contractions were similar in colon segments from WT, P2X2 and P2X3 KO mice. The mouse colon generates spontaneous migrating motor complexes (MMCs in vitro. The MMC frequency was higher in P2X2 KO compared to WT tissues; other parameters of the MMC were similar in colon segments from WT, P2X2 and P2X3 KO mice. 5-Hydroxytryptophan-induced fecal output was similar in WT, P2X2 and P2X3 KO mice. These data indicate that nicotinic receptors are located predominately on inhibitory motor neurons supplying the longitudinal muscle in the mouse colon. P2X2 or P2X3 subunit containing receptors are not localized to motorneurons supplying the longitudinal muscle. Synaptic transmission mediated by P2X2 or P2X3 subunit containing receptors is not required for propulsive motility in the mouse colon.

  16. Differential expression of the P2X7 receptor in ovarian surface epithelium during the oestrous cycle in the mouse.

    Science.gov (United States)

    Vázquez-Cuevas, F G; Cruz-Rico, A; Garay, E; García-Carrancá, A; Pérez-Montiel, D; Juárez, B; Arellano, R O

    2013-01-01

    Purinergic signalling has been proposed as an intraovarian regulatory mechanism. Of the receptors responsible for purinergic transmission, the P2X7 receptor is an ATP-gated cationic channel that displays a broad spectrum of cellular functions ranging from apoptosis to cell proliferation and tumourigenesis. In the present study, we investigated the functional expression of P2X7 receptors in ovarian surface epithelium (OSE). P2X7 protein was detected in the OSE layer of the mouse, both in situ and in primary cultures. In cultures, 2'(3')-O-(4-Benzoylbenzoyl)adenosine-5'-triphosphate (BzATP) activation of P2X7 receptors increased [Ca(2+)]i and induced apoptosis. The functionality of the P2X7 receptor was investigated in situ by intrabursal injection of BzATP on each day of the oestrous cycle and evaluation of apoptosis 24h using the terminal deoxyribonucleotidyl transferase-mediated dUTP-fluorescein nick end-labelling (TUNEL) assay. Maximum effects of BzATP were observed during pro-oestrus, with the effects being blocked by A438079, a specific P2X7 receptor antagonist. Immunofluorescence staining for P2X7 protein revealed more robust expression during pro-oestrus and in OSE regions behind the antral follicles, strongly supporting the notion that the differences in apoptosis can be explained by increased receptor expression, which is regulated during the oestrous cycle. Finally, P2X7 receptor expression was detected in the OSE layer of human ovaries, with receptor expression maintained in human ovaries diagnosed with cancer, as well as in the human ovarian carcinoma SKOV3 cell line.

  17. High susceptibility of metastatic cells derived from human prostate and colon cancer cells to TRAIL and sensitization of TRAIL-insensitive primary cells to TRAIL by 4,5-dimethoxy-2-nitrobenzaldehyde

    Directory of Open Access Journals (Sweden)

    Lee Jae-Won

    2011-04-01

    Full Text Available Abstract Background Tumor recurrence and metastasis develop as a result of tumors' acquisition of anti-apoptotic mechanisms and therefore, it is necessary to develop novel effective therapeutics against metastatic cancers. In this study, we showed the differential TRAIL responsiveness of human prostate adenocarcinoma PC3 and human colon carcinoma KM12 cells and their respective highly metastatic PC3-MM2 and KM12L4A sublines and investigated the mechanism underlying high susceptibility of human metastatic cancer cells to TRAIL. Results PC3-MM2 and KM12L4A cells with high level of c-Myc and DNA-PKcs were more susceptible to TRAIL than their poorly metastatic primary PC3 and KM12 cells, which was associated with down-regulation of c-FLIPL/S and Mcl-1 and up-regulation of the TRAIL receptor DR5 but not DR4 in both metastatic cells. Moreover, high susceptibility of these metastatic cells to TRAIL was resulted from TRAIL-induced potent activation of caspase-8, -9, and -3 in comparison with their primary cells, which led to cleavage and down-regulation of DNA-PKcs. Knockdown of c-Myc gene in TRAIL-treated PC3-MM2 cells prevented the increase of DR5 cell surface expression, caspase activation and DNA-PKcs cleavage and attenuated the apoptotic effects of TRAIL. Moreover, the suppression of DNA-PKcs level with siRNA in the cells induced the up-regulation of DR5 and active caspase-8, -9, and -3. We also found that 4,5-dimethoxy-2-nitrobenzaldehyde (DMNB, a specific inhibitor of DNA-PK, potentiated TRAIL-induced cytotoxicity and apoptosis in relatively TRAIL-insensitive PC3 and KM12 cells and therefore functioned as a TRAIL sensitizer. Conclusion This study showed the positive relationship between c-Myc expression in highly metastatic human prostate and colon cancer cells and susceptibility to TRAIL-induced apoptosis and therefore indicated that TRAIL might be used as an effective therapeutic modality for advanced metastatic cancers overexpressing c-Myc and

  18. C/2013 P2 Pan STARRS - The Manx Comet

    Science.gov (United States)

    Meech, Karen J.; Yang, Bin; Keane, Jacqueline; Hainaut, Olivier; Kleyna, Jan; Hsieh, Henry; Bauer, James; Wainscoat, Richard; Veres, Peter

    2014-11-01

    On Aug 4, 2013 an apparently asteroidal object was discovered by the Pan STARRS1 (PS1) survey telescope on Haleakala at magnitude 20.4 (corresponding to a nucleus radius between 1.4-2.9 km for albedos between 0.25-0.04). PS1 pre-recovery images taken on July 26 and on Aug. 3 allowed a good orbit to be determined. The orbit looks like that of a long-period comet with a semi major axis of 2720 AU and an eccentricity of 0.999. Shortly following the discovery, reports from small telescopes came in that there was low level activity associated with this object (at r = 3.45 AU), and the object was designated P/2013 P2 (Pan STARRS). The activity was not seen in images obtained with PS1, the Faulkes N telescope or the CFHT 3.6m, however the object was passing through a region of significant nebulosity. Deep images obtained on the CFHT on Aug. 8 and follow up images obtained with the Gemini North 8m telescope on Sep. 9 showed a very faint tail extending a few arcsec to PA=45 deg (inconsistent with the earlier reports). The object was observed using several facilities up until solar conjunction, and again after perihelion (Feb. 17, 2014) in March, with little increase in activity. A search of the NEOWISE archives show no detection during the cryogenic and immediate pos-cryogenic phases, so we can only place an upper limit on the nucleus size from these data. An object on a long-period comet orbit at this heliocentric distance typically should be very active, and our team hypothesized that this could either be a nearly-extinct comet or possibly inner solar system material ejected to the outer solar system during planet migration as predicted by various dynamical models. To distinguish between these scenarios, we obtained both optical and near-IR spectra of P/2013 P2 on 2014 May 7 and 21, when the object was at r=2.97 and 2.99 AU, respectively. Initial reductions show no emission lines. We will report on our spectra and imaging data, and discuss the implications for the origin

  19. BET bromodomain inhibition rescues erythropoietin differentiation of human erythroleukemia cell line UT7

    International Nuclear Information System (INIS)

    Goupille, Olivier; Penglong, Tipparat; Lefèvre, Carine; Granger, Marine; Kadri, Zahra; Fucharoen, Suthat; Maouche-Chrétien, Leila; Leboulch, Philippe; Chrétien, Stany

    2012-01-01

    Highlights: ► UT7 erythroleukemia cells are known to be refractory to differentiate. ► Brief JQ1 treatment initiates the first steps of erythroid differentiation program. ► Engaged UT7 cells then maturate in the presence of erythropoietin. ► Sustained JQ1 treatment inhibits both proliferation and erythroid differentiation. -- Abstract: Malignant transformation is a multistep process requiring oncogenic activation, promoting cellular proliferation, frequently coupled to inhibition of terminal differentiation. Consequently, forcing the reengagement of terminal differentiation of transformed cells coupled or not with an inhibition of their proliferation is a putative therapeutic approach to counteracting tumorigenicity. UT7 is a human leukemic cell line able to grow in the presence of IL3, GM-CSF and Epo. This cell line has been widely used to study Epo-R/Epo signaling pathways but is a poor model for erythroid differentiation. We used the BET bromodomain inhibition drug JQ1 to target gene expression, including that of c-Myc. We have shown that only 2 days of JQ1 treatment was required to transitory inhibit Epo-induced UT7 proliferation and to restore terminal erythroid differentiation. This study highlights the importance of a cellular erythroid cycle break mediated by c-Myc inhibition before initiation of the erythropoiesis program and describes a new model for BET bromodomain inhibitor drug application.

  20. BET bromodomain inhibition rescues erythropoietin differentiation of human erythroleukemia cell line UT7

    Energy Technology Data Exchange (ETDEWEB)

    Goupille, Olivier [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Penglong, Tipparat [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Thalassemia Research Center and Department of Clinical Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Thailand); Lefevre, Carine; Granger, Marine; Kadri, Zahra [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Fucharoen, Suthat [Thalassemia Research Center and Department of Clinical Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Thailand); Maouche-Chretien, Leila [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Leboulch, Philippe [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Genetics Division, Department of Medicine, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA (United States); Chretien, Stany, E-mail: stany.chretien@cea.fr [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France)

    2012-12-07

    Highlights: Black-Right-Pointing-Pointer UT7 erythroleukemia cells are known to be refractory to differentiate. Black-Right-Pointing-Pointer Brief JQ1 treatment initiates the first steps of erythroid differentiation program. Black-Right-Pointing-Pointer Engaged UT7 cells then maturate in the presence of erythropoietin. Black-Right-Pointing-Pointer Sustained JQ1 treatment inhibits both proliferation and erythroid differentiation. -- Abstract: Malignant transformation is a multistep process requiring oncogenic activation, promoting cellular proliferation, frequently coupled to inhibition of terminal differentiation. Consequently, forcing the reengagement of terminal differentiation of transformed cells coupled or not with an inhibition of their proliferation is a putative therapeutic approach to counteracting tumorigenicity. UT7 is a human leukemic cell line able to grow in the presence of IL3, GM-CSF and Epo. This cell line has been widely used to study Epo-R/Epo signaling pathways but is a poor model for erythroid differentiation. We used the BET bromodomain inhibition drug JQ1 to target gene expression, including that of c-Myc. We have shown that only 2 days of JQ1 treatment was required to transitory inhibit Epo-induced UT7 proliferation and to restore terminal erythroid differentiation. This study highlights the importance of a cellular erythroid cycle break mediated by c-Myc inhibition before initiation of the erythropoiesis program and describes a new model for BET bromodomain inhibitor drug application.

  1. Antileukemic Potential of Momordica charantia Seed Extracts on Human Myeloid Leukemic HL60 Cells

    Directory of Open Access Journals (Sweden)

    Ramani Soundararajan

    2012-01-01

    Full Text Available Momordica charantia (bitter gourd has been used in the traditional system of medicine for the treatment of various diseases. Anticancer activity of M. charantia extracts has been demonstrated by numerous in vitro and in vivo studies. In the present study, we investigated the differentiation inducing potential of fractionated M. charantia seed extracts in human myeloid HL60 cells. We found that the HL60 cells treated with the fractionated seed extracts differentiated into granulocytic lineage as characterized by NBT staining, CD11b expression, and specific esterase activity. The differentiation inducing principle was found to be heat-stable, and organic in nature. The differentiation was accompanied by a downregulation of c-myc transcript, indicating the involvement of c-myc pathway, at least in part, in differentiation. Taken together these results indicate that fractionated extracts of M. charantia seeds possess differentiation inducing activity and therefore can be evaluated for their potential use in differentiation therapy for leukemia in combination with other inducers of differentiation.

  2. Antileukemic Potential of Momordica charantia Seed Extracts on Human Myeloid Leukemic HL60 Cells

    Science.gov (United States)

    Soundararajan, Ramani; Prabha, Punit; Rai, Umesh; Dixit, Aparna

    2012-01-01

    Momordica charantia (bitter gourd) has been used in the traditional system of medicine for the treatment of various diseases. Anticancer activity of M. charantia extracts has been demonstrated by numerous in vitro and in vivo studies. In the present study, we investigated the differentiation inducing potential of fractionated M. charantia seed extracts in human myeloid HL60 cells. We found that the HL60 cells treated with the fractionated seed extracts differentiated into granulocytic lineage as characterized by NBT staining, CD11b expression, and specific esterase activity. The differentiation inducing principle was found to be heat-stable, and organic in nature. The differentiation was accompanied by a downregulation of c-myc transcript, indicating the involvement of c-myc pathway, at least in part, in differentiation. Taken together these results indicate that fractionated extracts of M. charantia seeds possess differentiation inducing activity and therefore can be evaluated for their potential use in differentiation therapy for leukemia in combination with other inducers of differentiation. PMID:22654956

  3. Reciprocal regulation of platelet responses to P2Y and thromboxane receptor activation.

    Science.gov (United States)

    Barton, J F; Hardy, A R; Poole, A W; Mundell, S J

    2008-03-01

    Thromboxane A(2) and ADP are two major platelet agonists that stimulate two sets of G protein-coupled receptors to activate platelets. Although aggregation responses to ADP and thromboxane desensitize, there are no reports currently addressing whether activation by one agonist may heterologously desensitize responses to the other. To demonstrate whether responses to ADP or U46619 may be modulated by prior treatment of platelets with the alternate agonist, revealing a level of cross-desensitization between receptor systems. Here we show that pretreatment of platelets with either agonist substantially desensitizes aggregation responses to the other agonist. Calcium responses to thromboxane receptor activation are desensitized by preactivation of P2Y(1) but not P2Y(12) receptors. This heterologous desensitization is mediated by a protein kinase C (PKC)-independent mechanism. Reciprocally, calcium responses to ADP are desensitized by pretreatment of platelets with the thromboxane analogue, U46619, and P2Y(12)-mediated inhibition of adenylate cyclase is also desensitized by pretreatment with U46619. In this direction, desensitization is comprised of two components, a true heterologous component that is PKC-independent, and a homologous component that is mediated through stimulated release of dense granule ADP. This study reveals cross-desensitization between ADP and thromboxane receptor signaling in human platelets. Cross-desensitization is mediated by protein kinases, involving PKC-dependent and independent pathways, and indicates that alterations in the activation state of one receptor may have effects upon the sensitivity of the other receptor system.

  4. Building a tracking detector for the P2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Marco [Institute of Nuclear Physics, Johannes Gutenberg University, Mainz (Germany); PRISMA Cluster of Excellence (Germany); Collaboration: P2-Collaboration

    2016-07-01

    The P2 Experiment aims to measure the weak mixing angle at low Q{sup 2} via the parity violating asymmetry in elastic electron-proton scattering. It will be located at the new Mainz Energy Recovery Superconducting Accelerator (MESA), which will provide a 150 μA beam of alternatingly polarized 150 MeV electrons. While the main asymmetry measurement is performed with integrating Cherenkov detectors, the tracking system is developed in order to determine the average momentum transfer of the electron and to reconstruct individual electron tracks for systematic studies. It will be built using the new technology of High Voltage Monolithic Active Pixel Sensors (HV-MAPS) made of silicon thinned to 50 μm. The main challenge for the tracking system are very high expected particle rates. The expected rate of electrons that are scattered in the liquid hydrogen target and hit the tracking system is of the order 10{sup 5}mm{sup -2}s{sup -1} and is overwhelmed by more than 10{sup 7} mm{sup -2}s{sup -1} bremsstrahlung photons. Each of the tracking layers is envisaged to have a disc-like geometry. They are arranged as two double layers. Since only limited sensor area is affordable, each layer is divided into four segments with about 15 degree azimutal coverage. This layout is presented and motivated by investigations on the expected hit rates and the sensor response.

  5. Improved Degree Search Algorithms in Unstructured P2P Networks

    Directory of Open Access Journals (Sweden)

    Guole Liu

    2012-01-01

    Full Text Available Searching and retrieving the demanded correct information is one important problem in networks; especially, designing an efficient search algorithm is a key challenge in unstructured peer-to-peer (P2P networks. Breadth-first search (BFS and depth-first search (DFS are the current two typical search methods. BFS-based algorithms show the perfect performance in the aspect of search success rate of network resources, while bringing the huge search messages. On the contrary, DFS-based algorithms reduce the search message quantity and also cause the dropping of search success ratio. To address the problem that only one of performances is excellent, we propose two memory function degree search algorithms: memory function maximum degree algorithm (MD and memory function preference degree algorithm (PD. We study their performance including the search success rate and the search message quantity in different networks, which are scale-free networks, random graph networks, and small-world networks. Simulations show that the two performances are both excellent at the same time, and the performances are improved at least 10 times.

  6. Pathophysiological consequences of receptor mistraffic: Tales from the platelet P2Y12 receptor.

    Science.gov (United States)

    Cunningham, Margaret R; Aungraheeta, Riyaad; Mundell, Stuart J

    2017-07-05

    Genetic variations in G protein-coupled receptor (GPCR) genes can disrupt receptor function in a wide variety of human genetic diseases, including platelet bleeding disorders. Platelets are critical for haemostasis with inappropriate platelet activation leading to the development of arterial thrombosis, which can result in heart attack and stroke whilst decreased platelet activity is associated with an increased risk of bleeding. GPCRs expressed on the surface of platelets play key roles in regulating platelet activity and therefore function. Receptors include purinergic receptors (P2Y 1 and P2Y 12 ), proteinase-activated receptor (PAR1 and PAR4) and thromboxane receptors (TPα), among others. Pharmacological blockade of these receptors forms a powerful therapeutic tool in the treatment and prevention of arterial thrombosis. With the advance of genomic technologies, there has been a substantial increase in the identification of naturally occurring rare and common GPCR variants. These variants include single-nucleotide polymorphisms (SNPs) and insertion or deletions that have the potential to alter GPCR expression or function. A number of defects in platelet GPCRs that disrupt receptor function have now been characterized in patients with mild bleeding disorders. This review will focus on rare, function-disrupting variants of platelet GPCRs with particular emphasis upon mutations in the P2Y 12 receptor gene that affect receptor traffic to modulate platelet function. Further this review will outline how the identification and characterization of function-disrupting GPCR mutations provides an essential link in translating our detailed understanding of receptor traffic and function in cell line studies into relevant human biological systems. Copyright © 2017. Published by Elsevier B.V.

  7. Direct induction of chondrogenic cells from human dermal fibroblast culture by defined factors.

    Directory of Open Access Journals (Sweden)

    Hidetatsu Outani

    Full Text Available The repair of large cartilage defects with hyaline cartilage continues to be a challenging clinical issue. We recently reported that the forced expression of two reprogramming factors (c-Myc and Klf4 and one chondrogenic factor (SOX9 can induce chondrogenic cells from mouse dermal fibroblast culture without going through a pluripotent state. We here generated induced chondrogenic (iChon cells from human dermal fibroblast (HDF culture with the same factors. We developed a chondrocyte-specific COL11A2 promoter/enhancer lentiviral reporter vector to select iChon cells. The human iChon cells expressed marker genes for chondrocytes but not fibroblasts, and were derived from non-chondrogenic COL11A2-negative cells. The human iChon cells formed cartilage but not tumors in nude mice. This approach could lead to the preparation of cartilage directly from skin in human, without going through pluripotent stem cells.

  8. Inverse agonism at the P2Y12 receptor and ENT1 transporter blockade contribute to platelet inhibition by ticagrelor.

    Science.gov (United States)

    Aungraheeta, Riyaad; Conibear, Alexandra; Butler, Mark; Kelly, Eamonn; Nylander, Sven; Mumford, Andrew; Mundell, Stuart J

    2016-12-08

    Ticagrelor is a potent antagonist of the P2Y 12 receptor (P2Y 12 R) and consequently an inhibitor of platelet activity effective in the treatment of atherothrombosis. Here, we sought to further characterize its molecular mechanism of action. Initial studies showed that ticagrelor promoted a greater inhibition of adenosine 5'-diphosphate (ADP)-induced Ca 2+ release in washed platelets vs other P2Y 12 R antagonists. This additional effect of ticagrelor beyond P2Y 12 R antagonism was in part as a consequence of ticagrelor inhibiting the equilibrative nucleoside transporter 1 (ENT1) on platelets, leading to accumulation of extracellular adenosine and activation of G s -coupled adenosine A 2A receptors. This contributed to an increase in basal cyclic adenosine monophosphate (cAMP) and vasodilator-stimulated phosphoprotein phosphorylation (VASP-P). In addition, ticagrelor increased platelet cAMP and VASP-P in the absence of ADP in an adenosine receptor-independent manner. We hypothesized that this increase originated from a direct effect on basal agonist-independent P2Y 12 R signaling, and this was validated in 1321N1 cells stably transfected with human P2Y 12 R. In these cells, ticagrelor blocked the constitutive agonist-independent activity of the P2Y 12 R, limiting basal G i -coupled signaling and thereby increasing cAMP levels. These data suggest that ticagrelor has the pharmacological profile of an inverse agonist. Based on our results showing insurmountable inhibition of ADP-induced Ca 2+ release and forskolin-induced cAMP, the mode of antagonism of ticagrelor also appears noncompetitive, at least functionally. In summary, our studies describe 2 novel modes of action of ticagrelor, inhibition of platelet ENT1 and inverse agonism at the P2Y 12 R that contribute to its effective inhibition of platelet activation. © 2016 by The American Society of Hematology.

  9. P2X7 mRNA expression in non-small cell lung cancer: MicroRNA regulation and prognostic value

    OpenAIRE

    BOLDRINI, LAURA; GIORDANO, MIRELLA; ALÌ, GRETA; MELFI, FRANCA; ROMANO, GAETANO; LUCCHI, MARCO; FONTANINI, GABRIELLA

    2014-01-01

    The human P2X7 receptor is significant and exhibits several functions in neoplasia. At present, little is known with regard to its regulation. P2X7 expression may be regulated post-transcriptionally and putative microRNA (miRNA) binding sites are considered to be involved. The aim of this study was to determine whether miRNAs (miR-21, let-7 g and miR-205) regulate P2X7 mRNA stability. In addition, the impact of P2X7 expression in patients with non-small cell lung cancer (NSCLC) was investigat...

  10. P2X receptor-ion channels in the inflammatory response in adipose tissue and pancreas-potential triggers in onset of type 2 diabetes?

    DEFF Research Database (Denmark)

    Novak, Ivana; Solini, Anna

    2018-01-01

    -cell and adipose tissue. In the former, P2Y and possibly some P2X receptors-ion channels regulate insulin secretion, but it is still debated whether excessive ATP can via P2X receptors impair β-cell function directly or whether cell damage is due to an excessive systemic release of cytokines. In human adipocytes......, the P2X7 receptor promotes the release of inflammatory cytokines, at least in part via inflammasome activation, likely contributing to systemic insulin resistance. This receptor-inflammasome system is also strongly activated in macrophages infiltrating both pancreas and adipose tissue, mediating...

  11. Combinatorial treatment of DNA and chromatin-modifying drugs cause cell death in human and canine osteosarcoma cell lines.

    Directory of Open Access Journals (Sweden)

    Venugopal Thayanithy

    Full Text Available Downregulation of microRNAs (miRNAs at the 14q32 locus stabilizes the expression of cMYC, thus significantly contributing to osteosarcoma (OS pathobiology. Here, we show that downregulation of 14q32 miRNAs is epigenetically regulated. The predicted promoter regions of miRNA clusters at 14q32 locus showed no recurrent patterns of differential methylation, but Saos2 cells showed elevated histone deacetylase (HDAC activity. Treatment with 4-phenylbutyrate increased acetylation of histones associated with 14q32 miRNAs, but interestingly, robust restoration of 14q32 miRNA expression, attenuation of cMYC expression, and induction of apoptosis required concomitant treatment with 5-Azacytidine, an inhibitor of DNA methylation. These events were associated with genome-wide gene expression changes including induction of pro-apoptotic genes and downregulation of cell cycle genes. Comparable effects were achieved in human and canine OS cells using the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA/Vorinostat and the DNA methylation inhibitor Zebularine (Zeb, with significantly more pronounced cytotoxicity in cells whose molecular phenotypes were indicative of aggressive biological behavior. These results suggested that the combination of these chromatin-modifying drugs may be a useful adjuvant in the treatment of rapidly progressive OS.

  12. P2RX7 purinoceptor: a therapeutic target for ameliorating the symptoms of duchenne muscular dystrophy.

    Directory of Open Access Journals (Sweden)

    Anthony Sinadinos

    2015-10-01

    Full Text Available Duchenne muscular dystrophy (DMD is the most common inherited muscle disease, leading to severe disability and death in young men. Death is caused by the progressive degeneration of striated muscles aggravated by sterile inflammation. The pleiotropic effects of the mutant gene also include cognitive and behavioral impairments and low bone density. Current interventions in DMD are palliative only as no treatment improves the long-term outcome. Therefore, approaches with a translational potential should be investigated, and key abnormalities downstream from the absence of the DMD product, dystrophin, appear to be strong therapeutic targets. We and others have demonstrated that DMD mutations alter ATP signaling and have identified P2RX7 purinoceptor up-regulation as being responsible for the death of muscles in the mdx mouse model of DMD and human DMD lymphoblasts. Moreover, the ATP-P2RX7 axis, being a crucial activator of innate immune responses, can contribute to DMD pathology by stimulating chronic inflammation. We investigated whether ablation of P2RX7 attenuates the DMD model mouse phenotype to assess receptor suitability as a therapeutic target.Using a combination of molecular, histological, and biochemical methods and behavioral analyses in vivo we demonstrate, to our knowledge for the first time, that genetic ablation of P2RX7 in the DMD model mouse produces a widespread functional attenuation of both muscle and non-muscle symptoms. In dystrophic muscles at 4 wk there was an evident recovery in key functional and molecular parameters such as improved muscle structure (minimum Feret diameter, p < 0.001, increased muscle strength in vitro (p < 0.001 and in vivo (p = 0.012, and pro-fibrotic molecular signatures. Serum creatine kinase (CK levels were lower (p = 0.025, and reduced cognitive impairment (p = 0.006 and bone structure alterations (p < 0.001 were also apparent. Reduction of inflammation and fibrosis persisted at 20 mo in leg (p = 0

  13. Down-regulation of telomerase activity in DLD-1 human colorectal adenocarcinoma cells by tocotrienol

    International Nuclear Information System (INIS)

    Eitsuka, Takahiro; Nakagawa, Kiyotaka; Miyazawa, Teruo

    2006-01-01

    As high telomerase activity is detected in most cancer cells, inhibition of telomerase by drug or dietary food components is a new strategy for cancer prevention. Here, we investigated the inhibitory effect of vitamin E, with particular emphasis on tocotrienol (unsaturated vitamin E), on human telomerase in cell-culture study. As results, tocotrienol inhibited telomerase activity of DLD-1 human colorectal adenocarcinoma cells in time- and dose-dependent manner, interestingly, with δ-tocotrienol exhibiting the highest inhibitory activity. Tocotrienol inhibited protein kinase C activity, resulting in down-regulation of c-myc and human telomerase reverse transcriptase (hTERT) expression, thereby reducing telomerase activity. In contrast to tocotrienol, tocopherol showed very weak telomerase inhibition. These results provide novel evidence for First time indicating that tocotrienol acts as a potent candidate regulator of telomerase and supporting the anti-proliferative function of tocotrienol

  14. Tools and drugs for uracil nucleotide-activated P2Y receptors.

    Science.gov (United States)

    Rafehi, Muhammad; Müller, Christa E

    2018-04-13

    P2Y receptors (P2YRs) are a family of G protein-coupled receptors activated by extracellular nucleotides. Physiological P2YR agonists include purine and pyrimidine nucleoside di- and triphosphates, such as ATP, ADP, UTP, UDP, nucleotide sugars, and dinucleotides. Eight subtypes exist, P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 11 , P2Y 12 , P2Y 13 , and P2Y 14 , which represent current or potential future drug targets. Here we provide a comprehensive overview of ligands for the subgroup of the P2YR family that is activated by uracil nucleotides: P2Y 2 (UTP, also ATP and dinucleotides), P2Y 4 (UTP), P2Y 6 (UDP), and P2Y 14 (UDP, UDP-glucose, UDP-galactose). The physiological agonists are metabolically unstable due to their fast hydrolysis by ectonucleotidases. A number of agonists with increased potency, subtype-selectivity and/or enzymatic stability have been developed in recent years. Useful P2Y 2 R agonists include MRS2698 (6-01, highly selective) and PSB-1114 (6-05, increased metabolic stability). A potent and selective P2Y 2 R antagonist is AR-C118925 (10-01). For studies of the P2Y 4 R, MRS4062 (3-15) may be used as a selective agonist, while PSB-16133 (10-06) represents a selective antagonist. Several potent P2Y 6 R agonists have been developed including 5-methoxyuridine 5'-O-((R p )α-boranodiphosphate) (6-12), PSB-0474 (3-11), and MRS2693 (3-26). The isocyanate MRS2578 (10-08) is used as a selective P2Y 6 R antagonist, although its reactivity and low water-solubility are limiting. With MRS2905 (6-08), a potent and metabolically stable P2Y 14 R agonist is available, while PPTN (10-14) represents a potent and selective P2Y 14 R antagonist. The radioligand [ 3 H]UDP can be used to label P2Y 14 Rs. In addition, several fluorescent probes have been developed. Uracil nucleotide-activated P2YRs show great potential as drug targets, especially in inflammation, cancer, cardiovascular and neurodegenerative diseases. Copyright © 2018. Published by Elsevier Inc.

  15. Apical P2XR contribute to [Ca2+]i signaling and Isc in mouse renal MCD.

    Science.gov (United States)

    Li, Liuzhe; Lynch, I Jeanette; Zheng, Wencui; Cash, Melanie N; Teng, Xueling; Wingo, Charles S; Verlander, Jill W; Xia, Shen-Ling

    2007-08-03

    We examined P2X receptor expression and distribution in the mouse collecting duct (CD) and their functional role in Ca(2+) signaling. Both P2X(1) and P2X(4) were detected by RT-PCR and Western blot. Immunohistochemistry demonstrated apical P2X(1) and P2X(4) immunoreactivity in principal cells in the outer medullary CD (OMCD) and inner medullary CD (IMCD). Luminal ATP induced an increase in Ca(2+) signaling in native medullary CD (MCD) as measured by fluorescence imaging. ATP also induced an increase in Ca(2+) signaling in MCD cells grown in primary culture but not in the presence of P2XR antagonist PPNDS. Short circuit current (I(sc)) measurement with mouse IMCD cells showed that P2XR agonist BzATP induced a larger I(sc) than did P2YR agonist UTP in the apical membrane. Our data reveal for the first time that P2X(1) and P2X(4) are cell-specific with prominent immunoreactivity in the apical area of MCD cells. The finding that P2XR blockade inhibits ATP-induced Ca(2+) signaling suggests that activation of P2XR is a key step in Ca(2+)-dependent purinergic signaling. The result that activation of P2XR produces large I(sc) indicates the necessity of P2XR in renal CD ion transport.

  16. Understanding the role of P2X7 in affective disorders – are glial cells the major players?

    Directory of Open Access Journals (Sweden)

    Leanne eStokes

    2015-07-01

    Full Text Available The pathophysiology of several psychiatric disorders has been linked to biomarkers of inflammation generating a theory of major depressive disorder as an inflammatory disease and infection and autoimmunity as major risk factors for schizophrenia. The idea of pro-inflammatory cytokines altering behavior is now well accepted however many questions remain. Microglia can produce a plethora of inflammatory cytokines and these cells appear to be critical in the link between inflammatory changes and depressive disorders. Microglia play a known role in sickness behavior which has many components of depressive-like behavior such as social withdrawal, sleep alterations, and anorexia. Numerous candidate genes have been identified for psychiatric disorders in the last decade. Single nucleotide polymorphisms in the human P2X7 gene have been linked to bipolar disorder, depression, and to the severity of depressive symptoms. P2X7 is a ligand-gated cation channel expressed on microglia with lower levels found on astrocytes and on some neuronal populations. In microglia P2X7 is a major regulator of pro-inflammatory cytokines of the interleukin-1 family. Genetic deletion of P2X7 in mice is protective for depressive behavior in addition to inflammatory responses. P2X7-/- mice have been shown to demonstrate anti-depressive-like behavior in forced swim and tail suspension behavioral tests and stressor-induced behavioral responses were blunted. Both neurochemical (norepinephrine, serotonin, dopamine and inflammatory changes have been observed in the brains of P2X7-/- mice. This review will discuss the recent evidence for involvement of P2X7 in the pathophysiology of depressive disorders and propose mechanisms by which altered signaling through this ion channel may affect the inflammatory state of the brain.

  17. Ion channel regulation by phosphoinositides analyzed with VSPs – PI(4,5P2 affinity, phosphoinositide selectivity, and PI(4,5P2 pool accessibility

    Directory of Open Access Journals (Sweden)

    Alexandra eRjasanow

    2015-06-01

    Full Text Available The activity of many proteins depends on the phosphoinositide (PI content of the membrane. E.g., dynamic changes of the concentration of PI(4,5P2 are cellular signals that regulate ion channels. The susceptibility of a channel to such dynamics depends on its affinity for PI(4,5P2. Yet, measuring affinities for endogenous PIs has not been possible directly, but has relied largely on the response to soluble analogs, which may not quantitatively reflect binding to native lipids.Voltage-sensitive phosphatases (VSPs turn over PI(4,5P2 to PI(4P when activated by depolarization. In combination with voltage-clamp electrophysiology VSPs are useful tools for rapid and reversible depletion of PI(4,5P2. Because cellular PI(4,5P2 is resynthesized rapidly, steady state PI(4,5P2 changes with the degree of VSP activation and thus depends on membrane potential.Here we show that titration of endogenous PI(4,5P2 with Ci-VSP allows for the quantification of relative PI(4,5P2 affinities of ion channels. The sensitivity of inward rectifier and voltage-gated K+ channels to Ci-VSP allowed for comparison of PI(4,5P2 affinities within and across channel subfamilies and detected changes of affinity in mutant channels. The results also reveal that VSPs are useful only for PI effectors with high binding specificity among PI isoforms, because PI(4,5P2 depletion occurs at constant overall PI level. Thus, Kir6.2, a channel activated by PI(4,5P2 and PI(4P was insensitive to VSP.Surprisingly, despite comparable PI(4,5P2 affinity as determined by Ci-VSP, the Kv7 and Kir channel families strongly differed in their sensitivity to receptor-mediated depletion of PI(4,5P2. While Kv7 members were highly sensitive to activation of PLC by Gq-coupled receptors, Kir channels were insensitive even when PI(4,5P2 affinity was lowered by mutation. We hypothesize that different channels may be associated with distinct pools of PI(4,5P2 that differ in their accessibility to PLC and VSPs.

  18. Knowledge Management Implementation in P2STPIBN as Internal TSO of BAPETEN

    International Nuclear Information System (INIS)

    Nugroho, D.H.

    2016-01-01

    Full text: Awareness of the importance of knowledge management implementation is growing since the launching in 2014 of BAPETEN’s (Nuclear Energy Regulatory Agency of Indonesia) vision to become a world-class nuclear energy regulatory agency. BAPETEN’s prime challenge arises since most of its human resources are still lacking experience, and many senior professionals have retired or are approaching retirement age. These challenges made P2STPIBN (Center for Regulatory Assessment on the Science and Technology of Nuclear Installation and Material) as an internal technical support organization (TSO) in BAPETEN aware that knowledge management should be implemented in advance. Following the BAPETEN Knowledge Management Guideline which was launched at the end of 2015, P2STPIBN, as part of BAPETEN, activated the knowledge management programme by creating a roadmap and programmes, such as a knowledge map and taxonomy, and a portal for knowledge repository (in progress). In the first quarter of FY of 2016 we started to build CoPs (community of practices) for the Nuclear Reactor Analysis, Nuclear Cyber Security and Nuclear Safety Culture based-on consideration of the needs on the most urgent knowledge. The CoP programme has run from the 2nd week of March 2016. The estimated challenges and anticipations are also discussed. (author

  19. Heterozygosity for the Mood Disorder-Associated Variant Gln460Arg Alters P2X7 Receptor Function and Sleep Quality.

    Science.gov (United States)

    Metzger, Michael W; Walser, Sandra M; Dedic, Nina; Aprile-Garcia, Fernando; Jakubcakova, Vladimira; Adamczyk, Marek; Webb, Katharine J; Uhr, Manfred; Refojo, Damian; Schmidt, Mathias V; Friess, Elisabeth; Steiger, Axel; Kimura, Mayumi; Chen, Alon; Holsboer, Florian; Arzt, Eduardo; Wurst, Wolfgang; Deussing, Jan M

    2017-11-29

    A single nucleotide polymorphism substitution from glutamine (Gln, Q) to arginine (Arg, R) at codon 460 of the purinergic P2X7 receptor (P2X7R) has repeatedly been associated with mood disorders. The P2X7R-Gln460Arg variant per se is not compromised in its function. However, heterologous expression of P2X7R-Gln460Arg together with wild-type P2X7R has recently been demonstrated to impair receptor function. Here we show that this also applies to humanized mice coexpressing both human P2X7R variants. Primary hippocampal cells derived from heterozygous mice showed an attenuated calcium uptake upon agonist stimulation. While humanized mice were unaffected in their behavioral repertoire under basal housing conditions, mice that harbor both P2X7R variants showed alterations in their sleep quality resembling signs of a prodromal disease stage. Also healthy heterozygous human subjects showed mild changes in sleep parameters. These results indicate that heterozygosity for the wild-type P2X7R and its mood disorder-associated variant P2X7R-Gln460Arg represents a genetic risk factor, which is potentially able to convey susceptibility to mood disorders. SIGNIFICANCE STATEMENT Depression and bipolar disorder are the most common mood disorders. The P2X7 receptor (P2X7R) regulates many cellular functions. Its polymorphic variant Gln460Arg has repeatedly been associated with mood disorders. Genetically engineered mice, with human P2X7R, revealed that heterozygous mice (i.e., they coexpress the disease-associated Gln460Arg variant together with its normal version) have impaired receptor function and showed sleep disturbances. Human participants with the heterozygote genotype also had subtle alterations in their sleep profile. Our findings suggest that altered P2X7R function in heterozygote individuals disturbs sleep and might increase the risk for developing mood disorders. Copyright © 2017 the authors 0270-6474/17/3711688-13$15.00/0.

  20. Chronic administration of the selective P2X3, P2X2/3 receptor antagonist, A-317491, transiently attenuates cancer-induced bone pain in mice

    DEFF Research Database (Denmark)

    Hansen, Rikke Rie; Nasser, Arafat; Falk, Sarah

    2012-01-01

    The purinergic P2X3 and P2X2/3 receptors are in the peripheral nervous system almost exclusively confined to afferent sensory neurons, where they are found both at peripheral and central synapses. The P2X3 receptor is implicated in both neuropathic and inflammatory pain. However, the role of the ......X3 receptor in chronic cancer-induced bone pain is less known. Here we investigated the effect of systemic acute and chronic administration of the selective P2X3, P2X2/3 receptor antagonist (5-[[[(3-Phenoxyphenyl)methyl][(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]carbonyl]-1...

  1. The cucurbitacins D, E, and I from Ecballium elaterium (L. upregulate the LC3 gene and induce cell-cycle arrest in human gastric cancer cell line AGS

    Directory of Open Access Journals (Sweden)

    Naser Jafargholizadeh

    2018-03-01

    Full Text Available Objective(s: Cucurbitacins exhibit a range of anti-cancer functions. We investigated the effects of cucurbitacins D, E, and I purified from Ecballium elaterium (L. A. Rich fruits on some apoptotic and autophagy genes in human gastric cancer cell line AGS. Materials and Methods: Using quantitative reverse transcription PCR (qRT-PCR, the expression of LC3, VEGF, BAX, caspase-3, and c-MYC genes were quantified in AGS cells 24 hr after treatment with cucurbitacins D, E, and I at concentrations 0.3, 0.1 and 0.5 μg/ml, respectively. Cell cycle and death were analyzed by flowcytometry. Results: Purified cucurbitacins induced sub-G1 cell-cycle arrest and cell death in AGS cells and upregulated LC3mRNA effectively, but showed a very low effect on BAX, caspase-3, and c-MYC mRNA levels. Also after treatment with cucurbitacin I at concentration 0.5 μg/ml, VEGF mRNA levels were increased about 4.4 times. Pairwise comparison of the effect of cucurbitacins D, E, and I on LC3 mRNA expression showed that the cucurbitacin I effect is 1.3 and 1.1 times that of cucurbitacins E and D, respectively; cucurbitacin D effect is 1.2 times that of cucurbitacin E (P-value

  2. A critical look at the function of the P2Y11 receptor

    DEFF Research Database (Denmark)

    Dreisig, Karin; Kornum, Birgitte Rahbek

    2016-01-01

    The P2Y11 receptor is a member of the purinergic receptor family. It has been overlooked, somewhat due to the lack of a P2ry11 gene orthologue in the murine genome, which prevents the generation of knockout mice, which have been so helpful for defining the roles of other P2Y receptors. Furthermor...

  3. P2X7 receptor activation induces cell death and microparticle release in murine erythroleukemia cells.

    NARCIS (Netherlands)

    Constantinescu, P.; Wang, B.; Kovacevic, K.; Jalilian, I.; Bosman, G.J.C.G.M.; Wiley, J.S.; Sluyter, R.

    2010-01-01

    Extracellular ATP induces cation fluxes in and impairs the growth of murine erythroleukemia (MEL) cells in a manner characteristic of the purinergic P2X7 receptor, however the presence of P2X7 in these cells is unknown. This study investigated whether MEL cells express functional P2X7. RT-PCR,

  4. Music2Share - Copyright-Compliant Music Sharing in P2P Systems

    NARCIS (Netherlands)

    Kalker, Ton; Epema, Dick H.J.; Hartel, Pieter H.; Lagendijk, R. (Inald) L.; van Steen, Martinus Richardus; van Steen, Maarten

    Peer-to-Peer (P2P) networks are generally considered to be free havens for pirated content, in particular with respect to music. We describe a solution for the problem of copyright infringement in P2P networks for music sharing. In particular, we propose a P2P protocol that integrates the functions

  5. Music2Share --- Copyright-Compliant Music Sharing in P2P Systems

    NARCIS (Netherlands)

    Kalker, T.; Epema, D.; Hartel, P.; Lagendijk, I.; van Steen, M.R.

    2004-01-01

    Peer-to-peer (P2P) networks are generally considered to be free havens for pirated content, in particular with respect to music. We describe a solution for the problem of copyright infringement in P2P networks for music sharing. In particular, we propose a P2P protocol that integrates the functions

  6. Generating a non-integrating human induced pluripotent stem cell bank from urine-derived cells.

    Directory of Open Access Journals (Sweden)

    Yanting Xue

    Full Text Available Induced pluripotent stem cell (iPS cell holds great potential for applications in regenerative medicine, drug discovery, and disease modeling. We describe here a practical method to generate human iPS cells from urine-derived cells (UCs under feeder-free, virus-free, serum-free condition and without oncogene c-MYC. We showed that this approach could be applied in a large population with different genetic backgrounds. UCs are easily accessible and exhibit high reprogramming efficiency, offering advantages over other cell types used for the purpose of iPS generation. Using the approach described in this study, we have generated 93 iPS cell lines from 20 donors with diverse genetic backgrounds. The non-viral iPS cell bank with these cell lines provides a valuable resource for iPS cells research, facilitating future applications of human iPS cells.

  7. Circadian ATP Release in Organotypic Cultures of the Rat Suprachiasmatic Nucleus Is Dependent on P2X7 and P2Y Receptors

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Irena; Bhattacharya, Anirban; Ivetic, Milorad; Bendová, Z.; Zemková, Hana

    2018-01-01

    Roč. 9, Mar 6 (2018), č. článku 192. ISSN 1663-9812 R&D Projects: GA ČR(CZ) GA16-12695S; GA ČR(CZ) GBP304/12/G069; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : suprachiasmatic nucleus * organotypic cultures * astrocytes * P2X7 receptor * P2Y1 receptor * P2Y2 receptor * pannexin-1 hemichannel * ATP release Subject RIV: FH - Neurology OBOR OECD: Neurosciences (including psychophysiology Impact factor: 4.400, year: 2016

  8. Anisotropic thermal properties and ferroelectric phase transitions in layered CuInP2S6 and CuInP2Se6 crystals

    Science.gov (United States)

    Liubachko, V.; Shvalya, V.; Oleaga, A.; Salazar, A.; Kohutych, A.; Pogodin, A.; Vysochanskii, Yu. M.

    2017-12-01

    Thermal diffusivity and thermal conductivity have been studied for the layered crystals CuInP2S6, CuInP2Se6 from 30 K to 350 K, showing a relevant thermal anisotropy. Heat is much more efficiently transferred within the layers than perpendicular to them. The ferrielectric transition in CuInP2S6 is proven to be clearly first order while the ferroelectric one in CuInP2Se6 has a weak first order character. The behavior of the thermal conductivity as a function of temperature in the ferroelectric phases shows that heat conduction is phonon driven. Disorder in the paraelectric phases due to hopping motions of Cu ions significantly reduces the thermal conductivity to extremely low values.

  9. P2X receptors in the cardiovascular system and their potential as therapeutic targets in disease.

    Science.gov (United States)

    Ralevic, Vera

    2015-01-01

    This review considers the expression and roles of P2X receptors in the cardiovascular system in health and disease and their potential as therapeutic targets. P2X receptors are ligand gated ion channels which are activated by the endogenous ligand ATP. They are formed from the assembly of three P2X subunit proteins from the complement of seven (P2X1-7), which can associate to form homomeric or heteromeric P2X receptors. The P2X1 receptor is widely expressed in the cardiovascular system, being located in the heart, in the smooth muscle of the majority of blood vessels and in platelets. P2X1 receptors expressed in blood vessels can be activated by ATP coreleased with noradrenaline as a sympathetic neurotransmitter, leading to smooth muscle depolarisation and contraction. There is evidence that the purinergic component of sympathetic neurotransmission is increased in hypertension, identifying P2X1 receptors as a possible therapeutic target in this disorder. P2X3 and P2X2/3 receptors are expressed on cardiac sympathetic neurones and may, through positive feedback of neuronal ATP at this prejunctional site, amplify sympathetic neurotransmission. Activation of P2X receptors expressed in the heart increases cardiac myocyte contractility, and an important role of the P2X4 receptor in this has been identified. Deletion of P2X4 receptors in the heart depresses contractile performance in models of heart failure, while overexpression of P2X4 receptors has been shown to be cardioprotective, thus P2X4 receptors may be therapeutic targets in the treatment of heart disease. P2X receptors have been identified on endothelial cells. Although immunoreactivity for all P2X1-7 receptor proteins has been shown on the endothelium, relatively little is known about their function, with the exception of the endothelial P2X4 receptor, which has been shown to mediate endothelium-dependent vasodilatation to ATP released during shear stress. The potential of P2X receptors as therapeutic targets

  10. Folksonomical P2P File Sharing Networks Using Vectorized KANSEI Information as Search Tags

    Science.gov (United States)

    Ohnishi, Kei; Yoshida, Kaori; Oie, Yuji

    We present the concept of folksonomical peer-to-peer (P2P) file sharing networks that allow participants (peers) to freely assign structured search tags to files. These networks are similar to folksonomies in the present Web from the point of view that users assign search tags to information distributed over a network. As a concrete example, we consider an unstructured P2P network using vectorized Kansei (human sensitivity) information as structured search tags for file search. Vectorized Kansei information as search tags indicates what participants feel about their files and is assigned by the participant to each of their files. A search query also has the same form of search tags and indicates what participants want to feel about files that they will eventually obtain. A method that enables file search using vectorized Kansei information is the Kansei query-forwarding method, which probabilistically propagates a search query to peers that are likely to hold more files having search tags that are similar to the query. The similarity between the search query and the search tags is measured in terms of their dot product. The simulation experiments examine if the Kansei query-forwarding method can provide equal search performance for all peers in a network in which only the Kansei information and the tendency with respect to file collection are different among all of the peers. The simulation results show that the Kansei query forwarding method and a random-walk-based query forwarding method, for comparison, work effectively in different situations and are complementary. Furthermore, the Kansei query forwarding method is shown, through simulations, to be superior to or equal to the random-walk based one in terms of search speed.

  11. Paracrine stimulation of P2X7 receptor by ATP activates a proliferative pathway in ovarian carcinoma cells.

    Science.gov (United States)

    Vázquez-Cuevas, Francisco G; Martínez-Ramírez, Angélica S; Robles-Martínez, Leticia; Garay, Edith; García-Carrancá, Alejandro; Pérez-Montiel, Delia; Castañeda-García, Carolina; Arellano, Rogelio O

    2014-11-01

    P2X7 is a purinergic receptor-channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non-cancerous and cancer patients were analyzed by immunohistochemistry. Ovarian surface epithelium in healthy tissue expressed P2X7 at a high level that was maintained throughout the cancer. The cell lines SKOV-3 and CAOV-3 were used to investigate P2X7 functions in OCA. In SKOV-3 cells, selective stimulation of P2X7 by 2'(3')-O-(4-benzoylbenzoyl) adenosine-5'-triphosphate (BzATP) induced a dose-dependent increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) but not cell death. Instead, BzATP increased the levels of phosphorylated ERK and AKT (pERK and pAKT), with an EC(50) of 44 ± 2 and 1.27 ± 0.5 μM, respectively; 10 μM BzATP evoked a maximum effect within 15 min that lasted for 120 min. Interestingly, basal levels of pERK and pAKT were decreased in the presence of apyrase in the medium, strongly suggesting an endogenous, ATP-mediated phenomenon. Accordingly: (i) mechanically stimulated cells generated a [Ca(2+)](i) increase that was abolished by apyrase; (ii) apyrase induced a decrease in culture viability, as measured by the MTS assay for mitochondrial activity; and (iii) incubation with 10 μM AZ10606120, a specific P2X7 antagonist and transfection with the dominant negative P2X7 mutant E496A, both reduced cell viability to 70.1 ± 8.9% and to 76.5 ± 5%, respectively, of control cultures. These observations suggested that P2X7 activity was auto-induced through ATP efflux; this increased pERK and pAKT levels that generated a positive feedback on cell viability. © 2014 Wiley Periodicals, Inc.

  12. Post-translational regulation of P2X receptor channels: modulation by phospholipids

    Directory of Open Access Journals (Sweden)

    Louis-Philippe eBernier

    2013-11-01

    Full Text Available P2X receptor channels mediate fast excitatory signaling by ATP and play major roles in sensory transduction, neuro-immune communication and inflammatory response. P2X receptors constitute a gene family of calcium-permeable ATP-gated cation channels therefore the regulation of P2X signaling is critical for both membrane potential and intracellular calcium homeostasis. Phosphoinositides (PIPn are anionic signaling phospholipids that act as functional regulators of many types of ion channels. Direct PIPn binding was demonstrated for several ligand- or voltage-gated ion channels, however no generic motif emerged to accurately predict lipid-protein binding sites. This review presents what is currently known about the modulation of the different P2X subtypes by phospholipids and about critical determinants underlying their sensitivity to PIPn levels in the plasma membrane.All functional mammalian P2X subtypes tested, with the notable exception of P2X5, have been shown to be positively modulated by PIPn, i.e. homomeric P2X1, P2X2, P2X3, P2X4, and P2X7, as well as heteromeric P2X1/5 and P2X2/3 receptors. Based on various results reported on the aforementioned subtypes including mutagenesis of the prototypical PIPn-sensitive P2X4 and PIPn-insensitive P2X5 receptor subtypes, an increasing amount of functional, biochemical and structural evidence converges on the modulatory role of a short polybasic domain located in the proximal C-terminus of P2X subunits. This linear motif, semi-conserved in the P2X family, seems necessary and sufficient for encoding direct modulation of ATP-gated channels by PIPn. Furthermore, the physiological impact of the regulation of ionotropic purinergic responses by phospholipids on pain pathways was recently revealed in the context of native crosstalks between phospholipase C-linked metabotropic receptors and P2X receptor channels in DRG sensory neurons and microglia.

  13. Analysis of the influence of nucleotidases on the apparent activity of exogenous ATP and ADP at P2Y1 receptors

    OpenAIRE

    Vigne, Paul; Philippe Breittmayer, Jean; Frelin, Christian

    1998-01-01

    ADP is a potent agonist of rat and human P2Y1 purinoceptors. ATP is a weak competitive antagonist. This study analyses the situation in which P2Y1 receptors are exposed to ATP in the presence of exogenous ecto-nucleotidases (apyrases) that have high or low ATPase/ADPase activity ratio.Rat brain capillary endothelial cells of the B10 clone express P2Y1 receptors that couple to intracellular Ca2+ mobilization. They have low endogenous ecto-ATPase and ecto-ADPase activities.ATP did not raise int...

  14. Synthesis of CaO-SiO2-P2O5 mesoporous bioactive glasses with high P2O5 content by evaporation induced self assembly process.

    Science.gov (United States)

    Zhao, Shan; Li, Yanbao; Li, Dongxu

    2011-02-01

    Mesoporous bioactive glasses (MBGs) of the CaO-SiO(2)-P(2)O(5) system containing relatively high P(2)O(5) contents (10-30 mol%) were prepared from a sol-gel. An evaporation-induced self-assembly (EISA) technique was used with poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (EO(20)-PO(70)-EO(20), P123) acting as a template. The structural, morphological and textural properties of MBGs were investigated by small-angle X-ray diffraction (SAXRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and a N(2) sorption/desorption technique. SAXRD and TEM results display the reduced long-range ordering of mesopores with increasing P(2)O(5) content. N(2) sorption/desorption analysis shows that all three samples exhibit a type IV isotherm with type H1 hysteresis loops, characteristic of independent cylindrical slim pore channels and this material has a Barret-Joyner-Halenda (BJH) model pore size of ~4 nm and BET specific surface area ~430 m(2)/g. NMR results indicate a more condensed framework for samples with 30 mol% P(2)O(5) than samples with 10 mol% P(2)O(5). For in vitro bioactivity tests where samples were soaked in simulated body fluid (SBF), samples with 30 mol% P(2)O(5) showed higher crystallinity than those with lower P(2)O(5) contents Silicon concentration increased in SBF solution during the soaking period, which indicates MBGs can be degradable in SBF solution.

  15. Altered endoribonuclease activity of apurinic/apyrimidinic endonuclease 1 variants identified in the human population.

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    Wan Cheol Kim

    Full Text Available Apurinic/apyrimidinic endonuclease 1 (APE1 is the major mammalian enzyme in the DNA base excision repair pathway and cleaves the DNA phosphodiester backbone immediately 5' to abasic sites. APE1 also has 3'-5' DNA exonuclease and 3' DNA phosphodiesterase activities, and regulates transcription factor DNA binding through its redox regulatory function. The human APE1 has recently been shown to endonucleolytically cleave single-stranded regions of RNA. Towards understanding the biological significance of the endoribonuclease activity of APE1, we examined eight different amino acid substitution variants of APE1 previously identified in the human population. Our study shows that six APE1 variants, D148E, Q51H, I64V, G241R, R237A, and G306A, exhibit a 76-85% reduction in endoribonuclease activity against a specific coding region of the c-myc RNA, yet fully retain the ability to cleave apurinic/apyrimidinic DNA. We found that two APE1 variants, L104R and E126D, exhibit a unique RNase inhibitor-resistant endoribonuclease activity, where the proteins cleave c-myc RNA 3' of specific single-stranded guanosine residues. Expression of L104R and E126D APE1 variants in bacterial Origami cells leads to a 60-80% reduction in colony formation and a 1.5-fold increase in cell doubling time, whereas the other variants, which exhibit diminished endoribonuclease activity, had no effect. These data indicate that two human APE1 variants exhibit a unique endoribonuclease activity, which correlates with their ability to induce cytotoxicity or slow down growth in bacterial cells and supports the notion of their biological functionality.

  16. Role of P2 Receptors as Modulators of Rat Eosinophil Recruitment in Allergic Inflammation.

    Directory of Open Access Journals (Sweden)

    Anael Viana Pinto Alberto

    Full Text Available ATP and other nucleotides are released from cells through regulated pathways or following the loss of plasma membrane integrity. Once outside the cell, these compounds can activate P2 receptors: P2X ionotropic receptors and G protein-coupled P2Y receptors. Eosinophils represent major effector cells in the allergic inflammatory response and they are, in fact, associated with several physiological and pathological processes. Here we investigate the expression of P2 receptors and roles of those receptors in murine eosinophils. In this context, our first step was to investigate the expression and functionality of the P2X receptors by patch clamping, our results showed a potency ranking order of ATP>ATPγS> 2meSATP> ADP> αβmeATP> βγmeATP>BzATP> UTP> UDP>cAMP. This data suggest the presence of P2X1, P2X2 and P2X7. Next we evaluate by microfluorimetry the expression of P2Y receptors, our results based in the ranking order of potency (UTP>ATPγS> ATP > UDP> ADP >2meSATP > αβmeATP suggests the presence of P2Y2, P2Y4, P2Y6 and P2Y11. Moreover, we confirmed our findings by immunofluorescence assays. We also did chemotaxis assays to verify whether nucleotides could induce migration. After 1 or 2 hours of incubation, ATP increased migration of eosinophils, as well as ATPγS, a less hydrolysable analogue of ATP, while suramin a P2 blocker abolished migration. In keeping with this idea, we tested whether these receptors are implicated in the migration of eosinophils to an inflammation site in vivo, using a model of rat allergic pleurisy. In fact, migration of eosinophils has increased when ATP or ATPγS were applied in the pleural cavity, and once more suramin blocked this effect. We have demonstrated that rat eosinophils express P2X and P2Y receptors. In addition, the activation of P2 receptors can increase migration of eosinophils in vitro and in vivo, an effect blocked by suramin.

  17. In Vitro Binding of [³H]PSB-0413 to P2Y₁₂ Receptors.

    Science.gov (United States)

    Dupuis, Arnaud; Heim, Véronique; Ohlmann, Philippe; Gachet, Christian

    2015-12-08

    The P2Y₁₂/ADP receptor plays a central role in platelet activation. Characterization of this receptor is mandatory for studying disorders associated with a P2Y₁₂ receptor defect and for evaluating P2Y₁₂ receptor agonists and antagonists. In the absence of suitable anti-P2Y₁₂ antibodies, radioligand binding assays are the only way to conduct such studies. While various radioligands were employed in the past for this purpose, none were found to be suitable for routine use. Described in this unit are protocols for quantitatively and qualitatively assessing P2Y₁₂ receptors with [³H]PSB-0413, a selective antagonist for this site. The saturation and competition assays described herein make possible the determination of P2Y₁₂ receptor density on cells, as well as the potencies and affinities of test agents at this site. Copyright © 2015 John Wiley & Sons, Inc.

  18. Protein kinase C isoforms in bovine aortic endothelial cells: role in regulation of P2Y- and P2U-purinoceptor-stimulated prostacyclin release.

    Science.gov (United States)

    Patel, V; Brown, C; Boarder, M R

    1996-05-01

    1. Enhanced synthesis of prostacyclin (PGI2) and inositol polyphosphates in bovine aortic endothelial cells in response to ATP and ADP is mediated by co-existing P2Y- and P2U-purinoceptors. Here we examine the regulation of these responses by isoforms of protein kinase C (PKC). 2. Immunoblots with antisera specific for 8 different PKC isoforms revealed the presence of alpha, epsilon and zeta, while no immunoreactivity was found for beta, gamma, delta, eta and theta isoforms. PKC-alpha was largely cytosolic in unstimulated cells and almost all translocated to the membrane (Triton X-100 soluble) after a 1 min treatment with the PKC activating phorbol myristate acetate (PMA); PKC-epsilon was always in a Triton X-100 insoluble membrane fraction, while PKC-zeta was found in both soluble and membrane bound (Triton X-100 soluble) forms in the unstimulated cells and was unaffected by PMA. 3. Treatment with PMA for 6 h led to a 90% downregulation of PKC-alpha, while the immunoreactivity to the epsilon and zeta isoforms remained largely unchanged. 4. After either 10 min or 6 h exposure to PMA the PGI2 response to activation of both receptors was enhanced, while the inositol 1,4,5-trisphosphate response to P2Y-purinoceptor activation was substantially attenuated and the P2U-purinoceptor response was unchanged. Thus the PGI2 response to PMA under conditions when 90% of the PKC-alpha was lost resembles that seen on acute stimulation of PKC by PMA, and the PGI2 response does not correlate with phospholipase C response. 5. Inhibition of PKC with the isoform non-selective inhibitors, Ro 31-8220 and Go 6850 abolished the PGI2 response to both P2U- and P2Y-purinoceptor stimulation. However, Go 6976, which preferentially inhibits Ca2+ sensitive isoforms (such as PKC-alpha) and not Ca2+ insensitive isoforms (such as PKC-epsilon), had no effect on the PGI2 response. 6. The results show that there is a requirement for PKC in the stimulation of PGI2 production by endothelial P2Y- and P2U

  19. Research of using mobile agents for information discovery in P2P networks

    International Nuclear Information System (INIS)

    Lan Yan; Yao Qing

    2003-01-01

    The technology of P2P is a new network-computing model that has great value of commerce and technology. After analyzing the current information discovery technology in P2P network, a new solution that is based on mobile agent is proposed. The mobile agent solution can reduce the need of bandwidth, be adapt to the dynamic of P2P network, and be asynchronous and be very fault tolerant. (authors)

  20. Novel protective role of endogenous cardiac myocyte P2X4 receptors in heart failure.

    Science.gov (United States)

    Yang, Tiehong; Shen, Jian-bing; Yang, Ronghua; Redden, John; Dodge-Kafka, Kimberly; Grady, James; Jacobson, Kenneth A; Liang, Bruce T

    2014-05-01

    Heart failure (HF), despite continuing progress, remains a leading cause of mortality and morbidity. P2X4 receptors (P2X4R) have emerged as potentially important molecules in regulating cardiac function and as potential targets for HF therapy. Transgenic P2X4R overexpression can protect against HF, but this does not explain the role of native cardiac P2X4R. Our goal is to define the physiological role of endogenous cardiac myocyte P2X4R under basal conditions and during HF induced by myocardial infarction or pressure overload. Mice established with conditional cardiac-specific P2X4R knockout were subjected to left anterior descending coronary artery ligation-induced postinfarct or transverse aorta constriction-induced pressure overload HF. Knockout cardiac myocytes did not show P2X4R by immunoblotting or by any response to the P2X4R-specific allosteric enhancer ivermectin. Knockout hearts showed normal basal cardiac function but depressed contractile performance in postinfarct and pressure overload models of HF by in vivo echocardiography and ex vivo isolated working heart parameters. P2X4R coimmunoprecipitated and colocalized with nitric oxide synthase 3 (eNOS) in wild-type cardiac myocytes. Mice with cardiac-specific P2X4R overexpression had increased S-nitrosylation, cyclic GMP, NO formation, and were protected from postinfarct and pressure overload HF. Inhibitor of eNOS, L-N(5)-(1-iminoethyl)ornithine hydrochloride, blocked the salutary effect of cardiac P2X4R overexpression in postinfarct and pressure overload HF as did eNOS knockout. This study establishes a new protective role for endogenous cardiac myocyte P2X4R in HF and is the first to demonstrate a physical interaction between the myocyte receptor and eNOS, a mediator of HF protection. © 2014 American Heart Association, Inc.

  1. The roles of P2Y2 purinergic receptors in osteoblasts and mechanotransduction.

    Directory of Open Access Journals (Sweden)

    Yanghui Xing

    Full Text Available We previously demonstrated, using osteoblastic MC3T3-E1 cells, that P2Y2 purinergic receptors are involved in osteoblast mechanotransduction. In this study, our objective was to further investigate, using a knockout mouse model, the roles of P2Y2 receptors in bone mechanobiology. We first examined bone structure with micro-CT and measured bone mechanical properties with three point bending experiments in both wild type mice and P2Y2 knockout mice. We found that bones from P2Y2 knockout mice have significantly decreased bone volume, bone thickness, bone stiffness and bone ultimate breaking force at 17 week old age. In order to elucidate the mechanisms by which P2Y2 receptors contribute to bone biology, we examined differentiation and mineralization of bone marrow cells from wild type and P2Y2 knockout mice. We found that P2Y2 receptor deficiency reduces the differentiation and mineralization of bone marrow cells. Next, we compared the response of primary osteoblasts, from both wild type and P2Y2 knockout mice, to ATP and mechanical stimulation (oscillatory fluid flow, and found that osteoblasts from wild type mice have a stronger response, in terms of ERK1/2 phosphorylation, to both ATP and fluid flow, relative to P2Y2 knockout mice. However, we did not detect any difference in ATP release in response to fluid flow between wild type and P2Y2 knock out osteoblasts. Our findings suggest that P2Y2 receptors play important roles in bone marrow cell differentiation and mineralization as well as in bone cell mechanotransduction, leading to an osteopenic phenotype in P2Y2 knockout mice.

  2. Potential Involvement of P2 Receptors in the Pathological Processes of Hyperthyroidism: A Pilot Study.

    Science.gov (United States)

    Hong, Wu; Li, Guodong; Nie, Yijun; Zou, Lifang; Zhang, Xi; Liu, Shuangmei; Li, Guilin; Xu, Hong; Zhang, Chun-Ping; Liang, Shangdong

    2016-05-01

    Symptoms of hyperthyroidism manifest mainly as changes in the nervous and metabolic systems. Whether P2X receptors (ionotropic ATP purinergic receptors, including P2X3 receptor and P2X7 receptor) are involved in the alterations of these disorders still remains unclear. Thus, this study aimed to assess the association of hyperthyroidism with the expression of P2X3 and P2X7 receptors and the concentrations of ATP in blood leukocytes and catecholamine. Twelve healthy subjects and twelve patients diagnosed with hyperthyroidism were recruited. Serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) levels had been detected by chemiluminescence method. Meanwhile, the catecholamine levels (including adrenaline, noradrenaline, and dopamine) in plasma, ATP level and P2X receptors (including P2X3 receptor and P2X7 receptor) in peripheral blood had been detected by high performance liquid chromatography, bioluminescence method, and reverse transcription polymerase chain reaction, respectively. Levels of epinephrine and norepinephrine were significantly higher in the hyperthyroidism group compared with the control group. The concentration of ATP in the hyperthyroidism group was significantly higher than its in the control group. The expression of P2X3 mRNA and P2X7 mRNA in hyperthyroidism group were significantly increased compared with those in control group. In a conclusion, there is a relationship between the elevated expression of P2X3 receptor and P2X7 receptor in peripheral blood leukocytes and high serum epinephrine and norepinephrine levels in hyperthyroidism patients. © 2016 by the Association of Clinical Scientists, Inc.

  3. Deletion of GOLGA2P3Y but not GOLGA2P2Y is a risk factor for oligozoospermia.

    Science.gov (United States)

    Sen, Sanjukta; Agarwal, Rupesh; Ambulkar, Prafulla; Hinduja, Indira; Zaveri, Kusum; Gokral, Jyotsna; Pal, Asoke; Modi, Deepak

    2016-02-01

    The AZFc locus on the human Y chromosome harbours several multicopy genes, some of which are required for spermatogenesis. It is believed that deletion of one or more copies of these genes is a cause of infertility in some men. GOLGA2LY is one of the genes in the AZFc locus and it exists in two copies, GOLGA2P2Y and GOLGA2P3Y. The involvement of GOLGA2LY gene copy deletions in male infertility, however, is unknown. This study aimed to investigate the association of deletions of GOLGA2P2Y and GOLGA2P3Y gene copies with male infertility and with sperm concentration and motility. The frequency of GOLGA2P3Y deletion was significantly higher in oligozoospermic men compared with normozoospermic men (7.7% versus 1.2%; P = 0.0001), whereas the frequency of GOLGA2P2Y deletion was comparable between oligozoospermic and normozoospermic men (10.3% versus 11.3%). The deletion of GOLGA2P3Y but not GOLGA2P2Y was significantly higher (P = 0.03) in men with gr/gr rearrangements, indicating that GOLGA2P3Y deletions increase the susceptibility of men with gr/gr rearrangements to oligozoospermia. Furthermore, men with GOLGA2P3Y deletion had reduced sperm concentration and motility compared with men without deletion or with deletion of GOLGA2P2Y. These findings indicate GOLGA2P3Y gene copy may be candidate AZFc gene for male infertility. Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  4. Cloning and Characterization of the Acidic Ribosomal Protein P2 of Cryptosporidium parvum, a New 17-Kilodalton Antigen▿

    Science.gov (United States)

    Priest, Jeffrey W.; Kwon, James P.; Montgomery, Joel M.; Bern, Caryn; Moss, Delynn M.; Freeman, Amanda R.; Jones, Cara C.; Arrowood, Michael J.; Won, Kimberly Y.; Lammie, Patrick J.; Gilman, Robert H.; Mead, Jan R.

    2010-01-01

    Cryptosporidium infection is commonly observed among children and immunocompromised individuals in developing countries, but large-scale outbreaks of disease among adults have not been reported. In contrast, outbreaks of cryptosporidiosis in the United States and Canada are increasingly common among patients of all ages. Thus, it seems likely that residents of regions where Cryptosporidium is highly endemic acquire some level of immunity, while residents of the developed world do not. A new immunodominant Cryptosporidium parvum antigen in the 15- to 17-kDa size range was identified as the Cryptosporidium parvum 60S acidic ribosomal protein P2 (CpP2). We developed a recombinant protein-based enzyme-linked immunosorbent assay for serologic population surveillance for antibodies that was 89% sensitive and 92% specific relative to the results of the large-format Western blot assay. The human IgG response is directed almost exclusively toward the highly conserved, carboxy-terminal 15 amino acids of the protein. Although IgG antibody cross-reactivity was documented with sera from patients with acute babesiosis, the development of an anti-CpP2 antibody response in our Peru study population correlated better with Cryptosporidium infection than with infection by any other parasitic protozoan. In Haiti, the prevalence of antibodies to CpP2 plateaus at 11 to 20 years of age. Because anti-CpP2 IgG antibodies were found only among residents of countries in the developing world where Cryptosporidium infection occurs early and often, we propose that this response may be a proxy for the intensity of infection and for acquired immunity. PMID:20410328

  5. Cleavage sites in the polypeptide precursors of poliovirus protein P2-X

    International Nuclear Information System (INIS)

    Selmer, B.L.; Hanecak, R.; Anderson, C.W.; Wimmer, E.

    1981-01-01

    Partial amino-terminal sequence analysis has been performed on the three major polypeptide products (P2-3b, P2-5b, and P2-X) from the central region (P2) of the poliovirus polyprotein, and this analysis precisely locates the amino termini of these products with respect to the nucleotide sequence of the poliovirus RNA genome. Like most of the products of the replicase region (P3), the amino termini of P2-5b and P2-X are generated by cleavage between glutamine and glycine residues. Thus, P2-5b and P2-X are probably both produced by the action of a singly (virus-encoded.) proteinase. The amino terminus of P2-3b, on the other hand, is produced by a cleavage between the carboxy-terminal tyrosine of VP1 and the glycine encoded by nucleotides 3381-3383. This result may suggest that more than one proteolytic activity is required for the complete processing of the poliovirus polyprotein

  6. Transformation of Astrocytes to a Neuroprotective Phenotype by Microglia via P2Y1 Receptor Downregulation

    Directory of Open Access Journals (Sweden)

    Youichi Shinozaki

    2017-05-01

    Full Text Available Microglia and astrocytes become reactive following traumatic brain injury (TBI. However, the coordination of this reactivity and its relation to pathophysiology are unclear. Here, we show that microglia transform astrocytes into a neuroprotective phenotype via downregulation of the P2Y1 purinergic receptor. TBI initially caused microglial activation in the injury core, followed by reactive astrogliosis in the peri-injured region and formation of a neuroprotective astrocyte scar. Equivalent changes to astrocytes were observed in vitro after injury. This change in astrocyte phenotype resulted from P2Y1 receptor downregulation, mediated by microglia-derived cytokines. In mice, astrocyte-specific P2Y1 receptor overexpression (Astro-P2Y1OE counteracted scar formation, while astrocyte-specific P2Y1 receptor knockdown (Astro-P2Y1KD facilitated scar formation, suggesting critical roles of P2Y1 receptors in the transformation. Astro-P2Y1OE and Astro-P2Y1KD mice showed increased and reduced neuronal damage, respectively. Altogether, our findings indicate that microglia-astrocyte interaction, involving a purinergic signal, is essential for the formation of neuroprotective astrocytes.

  7. Tungsten phosphanylarylthiolato complexes [W{PhP(2-SC6H4)2-kappa3S,S',P} 2] and [W{P(2-SC6H4)3-kappa4S,S',S",P}2]: synthesis, structures and redox chemistry.

    Science.gov (United States)

    Hildebrand, Alexandra; Lönnecke, Peter; Silaghi-Dumitrescu, Luminita; Hey-Hawkins, Evamarie

    2008-09-14

    PhP(2-SHC6H4)2 (PS2H2) reacts with WCl6 with reduction of tungsten to give the air-sensitive tungsten(IV) complex [W{PhP(2-SC6H4)2-kappa(3)S,S',P}2] (1). 1 is oxidised in air to [WO{PhPO(2-SC6H4)2-kappa(3)S,S',O}{PhP(2-SC6H4)2-kappa(3)S,S',P}] (2). The attempted synthesis of 2 by reaction of 1 with iodosobenzene as oxidising agent was unsuccessful. [W{P(2-SC6H4)3-kappa(4)S,S',S",P}2] (3) was formed in the reaction of P(2-SHC6H4)3 (PS3H3) with WCl6. The W(VI) complex 3 contains two PS3(3-) ligands, each coordinated in a tetradentate fashion resulting in a tungsten coordination number of eight. The reaction of 3 with AgBF4 yields the dinuclear tungsten complex [W2{P(2-SC6H4)3-kappa(4)S,S',S",P}3]BF4 (4). Complexes 1-4 were characterised by spectral methods and X-ray structure determination.

  8. Microglia P2Y6 receptor is related to Parkinson’s disease through neuroinflammatory process

    Directory of Open Access Journals (Sweden)

    Xiaodong Yang

    2017-02-01

    Full Text Available Abstract Background Microglia in the central nervous system (CNS were reported to play crucial role in neurodegeneration. Previous studies showed that P2Y6 receptor (P2Y6R mainly contributed to microglia activation and phagocytosis in CNS. However, the level of P2Y6R in Parkinson’s disease (PD patients is unclear. Therefore, we measured the level of P2Y6R in PD patients and speculated whether it could be a potential biomarker for PD. Given on the basis that P2Y6R was higher in PD patients, we further explored the mechanisms underlying P2Y6R in the pathogenesis of PD. Methods We tested the expression level of P2Y6R in the peripheral blood mononuclear cells (PBMCs among 145 PD patients, 170 healthy controls, and 30 multiple system atrophy (MSA patients. We also used a lipopolysaccharide (LPS-stimulated microglial cell culture model to investigate (i the effects of LPS on P2Y6R expression with western blot and RT-PCR, (ii the effects of LPS on UDP expression using HPLC, (iii the effects of UDP/P2Y6R signaling on cytokine expression using western blot, RT-PCR, and ELISA, and (iv the signaling pathways activated by the P2Y6R involved in the neuroinflammation. Results Expression levels of P2Y6R in PD patients were higher than healthy controls and MSA patients. P2Y6R could be a good biomarker of PD. P2Y6R was also upregulated in LPS-treated BV-2 cells and involved in proinflammatory cytokine release through an autocrine loop based on LPS-triggered UDP secretion and accelerated neuroinflammatory responses through the ERK1/2 pathway. Importantly, blocking UDP/P2Y6R signaling could reverse these pathological processes. Conclusions P2Y6R may be a potential clinical biomarker of PD. Blocking P2Y6R may be a potential therapeutic approach to the treatment of PD patients through inhibition of microglia-activated neuroinflammation.

  9. Validation of antibodies for neuroanatomical localization of the P2Y receptor in macaque brain

    DEFF Research Database (Denmark)

    Dreisig, Karin; Degn, Matilda; Sund, Louise

    2016-01-01

    Focus on the purinergic receptor P2Y11 has increased following the finding of an association between the sleep disorder narcolepsy and a genetic variant in P2RY11 causing decreased gene expression. Narcolepsy is believed to arise from an autoimmune destruction of the hypothalamic neurons that pro......Focus on the purinergic receptor P2Y11 has increased following the finding of an association between the sleep disorder narcolepsy and a genetic variant in P2RY11 causing decreased gene expression. Narcolepsy is believed to arise from an autoimmune destruction of the hypothalamic neurons...

  10. Oxygen/glucose deprivation increases the integration of recombinant P2X7 receptors into the plasma membrane of HEK293 cells

    International Nuclear Information System (INIS)

    Milius, Doreen; Groeger-Arndt, Helke; Stanchev, Doychin; Lange-Dohna, Christine; Rossner, Steffen; Sperlagh, Beata; Wirkner, Kerstin; Illes, Peter

    2007-01-01

    Recombinant human P2X 7 receptors, C-terminally labelled with enhanced green fluorescent protein (P2X 7 -EGFP), were transiently expressed in HEK293 cells. Activation of these receptors by their preferential agonist 2',3'-O-(4-benzoylbenzoyl)-ATP (BzATP) induced inward currents and propidium ion uptake indicating the opening of cationic channels and of large pores permeable for dye molecules, respectively. Two mutants of P2X 7 receptors (P2X 7 -EGFP-I568N, -E496A) representing polymorphisms in the P2X 7 gene known to interfere with normal receptor-trafficking and with optimal assembly of its subunits, responded with much lower current amplitudes to BzATP than their wild-type counterpart. Similarly, the normal propidium ion uptake induced by BzATP at the wild-type P2X 7 receptor was abolished by the two mutants. Confocal laser scanning microscopy indicated that in vitro ischemia of 12 h duration increased the integration of P2X 7 -EGFP, but not of its two mutants, into the plasma membrane of HEK293 cells. Further, this ischemic stimulus facilitated the current response to BzATP in HEK293 cells permanently transfected with P2X 7 receptors. Finally, the fluorescence intensity per cell measured by flow cytometry and P2X 7 antibodies directed against an extracellular, but not an intracellular epitope of the receptor, were also increased. In conclusion, P2X 7 receptors may alter their trafficking properties during ischemia and thereby contribute to the ATP-induced damage of various cell-types including neurons

  11. Automation of POST Cases via External Optimizer and "Artificial p2" Calculation

    Science.gov (United States)

    Dees, Patrick D.; Zwack, Mathew R.

    2017-01-01

    optimizer functions like any other gradient-based optimizer. It has a specified variable to optimize whose value is represented as optval, a set of dependent constraints to meet with associated forms and tolerances whose value is represented as p2, and a set of independent variables known as the u-vector to modify in pursuit of optimality. Each of these quantities are calculated or manipulated at a certain phase within the trajectory. The optimizer is further constrained by the requirement that the input u-vector must result in a trajectory which proceeds through each of the prescribed events in the input file. For example, if the input u-vector causes the vehicle to crash before it can achieve the orbital parameters required for a parking orbit, then the run will fail without engaging the optimizer, and a p2 value of exactly zero is returned. This poses a problem, as this "non-connecting" region of the u-vector space is far larger than the "connecting" region which returns a non-zero value of p2 and can be worked on by the internal optimizer. Finding this connecting region and more specifically the global optimum within this region has traditionally required the use of an expert analyst.

  12. Immunocytochemical analysis of P2X2 in rat circumvallate taste buds.

    Science.gov (United States)

    Yang, Ruibiao; Montoya, Alana; Bond, Amanda; Walton, Jenna; Kinnamon, John C

    2012-05-23

    Our laboratory has shown that classical synapses and synaptic proteins are associated with Type III cells. Yet it is generally accepted that Type II cells transduce bitter, sweet and umami stimuli. No classical synapses, however, have been found associated with Type II cells. Recent studies indicate that the ionotropic purinergic receptors P2X2/P2X3 are present in rodent taste buds. Taste nerve processes express the ionotropic purinergic receptors (P2X2/P2X3). P2X2/P2X3(Dbl-/-) mice are not responsive to sweet, umami and bitter stimuli, and it has been proposed that ATP acts as a neurotransmitter in taste buds. The goal of the present study is to learn more about the nature of purinergic contacts in rat circumvallate taste buds by examining immunoreactivity to antisera directed against the purinergic receptor P2X2. P2X2-like immunoreactivity is present in intragemmal nerve processes in rat circumvallate taste buds. Intense immunoreactivity can also be seen in the subgemmal nerve plexuses located below the basal lamina. The P2X2 immunoreactive nerve processes also display syntaxin-1-LIR. The immunoreactive nerves are in close contact with the IP(3)R3-LIR Type II cells and syntaxin-1-LIR and/or 5-HT-LIR Type III cells. Taste cell synapses are observed only from Type III taste cells onto P2X2-LIR nerve processes. Unusually large, "atypical" mitochondria in the Type II taste cells are found only at close appositions with P2X2-LIR nerve processes. P2X2 immunogold particles are concentrated at the membranes of nerve processes at close appositions with taste cells. Based on our immunofluorescence and immunoelectron microscopical studies we believe that both perigemmal and most all intragemmal nerve processes display P2X2-LIR. Moreover, colloidal gold immunoelectron microscopy indicates that P2X2-LIR in nerve processes is concentrated at sites of close apposition with Type II cells. This supports the hypothesis that ATP may be a key neurotransmitter in taste transduction

  13. Immunocytochemical analysis of P2X2 in rat circumvallate taste buds

    Directory of Open Access Journals (Sweden)

    Yang Ruibiao

    2012-05-01

    Full Text Available Abstract Background Our laboratory has shown that classical synapses and synaptic proteins are associated with Type III cells. Yet it is generally accepted that Type II cells transduce bitter, sweet and umami stimuli. No classical synapses, however, have been found associated with Type II cells. Recent studies indicate that the ionotropic purinergic receptors P2X2/P2X3 are present in rodent taste buds. Taste nerve processes express the ionotropic purinergic receptors (P2X2/P2X3. P2X2/P2X3Dbl−/− mice are not responsive to sweet, umami and bitter stimuli, and it has been proposed that ATP acts as a neurotransmitter in taste buds. The goal of the present study is to learn more about the nature of purinergic contacts in rat circumvallate taste buds by examining immunoreactivity to antisera directed against the purinergic receptor P2X2. Results P2X2-like immunoreactivity is present in intragemmal nerve processes in rat circumvallate taste buds. Intense immunoreactivity can also be seen in the subgemmal nerve plexuses located below the basal lamina. The P2X2 immunoreactive nerve processes also display syntaxin-1-LIR. The immunoreactive nerves are in close contact with the IP3R3-LIR Type II cells and syntaxin-1-LIR and/or 5-HT-LIR Type III cells. Taste cell synapses are observed only from Type III taste cells onto P2X2-LIR nerve processes. Unusually large, “atypical” mitochondria in the Type II taste cells are found only at close appositions with P2X2-LIR nerve processes. P2X2 immunogold particles are concentrated at the membranes of nerve processes at close appositions with taste cells. Conclusions Based on our immunofluorescence and immunoelectron microscopical studies we believe that both perigemmal and most all intragemmal nerve processes display P2X2-LIR. Moreover, colloidal gold immunoelectron microscopy indicates that P2X2-LIR in nerve processes is concentrated at sites of close apposition with Type II cells. This supports the hypothesis

  14. Non-nucleotide Agonists Triggering P2X7 Receptor Activation and Pore Formation

    Directory of Open Access Journals (Sweden)

    Francesco Di Virgilio

    2018-02-01

    Full Text Available The P2X7 receptor (P2X7R is a ligand-gated plasma membrane ion channel belonging to the P2X receptor subfamily activated by extracellular nucleotides. General consensus holds that the physiological (and maybe the only agonist is ATP. However, scattered evidence generated over the last several years suggests that ATP might not be the only agonist, especially at inflammatory sites. Solid data show that NAD+ covalently modifies the P2X7R of mouse T lymphocytes, thus lowering the ATP threshold for activation. Other structurally unrelated agents have been reported to activate the P2X7R via a poorly understood mechanism of action: (a the antibiotic polymyxin B, possibly a positive allosteric P2X7R modulator, (b the bactericidal peptide LL-37, (c the amyloidogenic β peptide, and (d serum amyloid A. Some agents, such as Alu-RNA, have been suggested to activate the P2X7R acting on the intracellular N- or C-terminal domains. Mode of P2X7R activation by these non-nucleotide ligands is as yet unknown; however, these observations raise the intriguing question of how these different non-nucleotide ligands may co-operate with ATP at inflammatory or tumor sites. New information obtained from the cloning and characterization of the P2X7R from exotic mammalian species (e.g., giant panda and data from recent patch-clamp studies are strongly accelerating our understanding of P2X7R mode of operation, and may provide hints to the mechanism of activation of P2X7R by non-nucleotide ligands.

  15. Knocking out P2X receptors reduces transmitter secretion in taste buds

    Science.gov (United States)

    Huang, Yijen A.; Stone, Leslie M.; Pereira, Elizabeth; Yang, Ruibiao; Kinnamon, John C.; Dvoryanchikov, Gennady; Chaudhari, Nirupa; Finger, Thomas E.; Kinnamon, Sue C.; Roper, Stephen D.

    2011-01-01

    In response to gustatory stimulation, taste bud cells release a transmitter, ATP, that activates P2X2 and P2X3 receptors on gustatory afferent fibers. Taste behavior and gustatory neural responses are largely abolished in mice lacking P2X2 and P2X3 receptors (P2X2 and P2X3 double knockout, or “DKO” mice). The assumption has been that eliminating P2X2 and P2X3 receptors only removes postsynaptic targets but that transmitter secretion in mice is normal. Using functional imaging, ATP biosensor cells, and a cell-free assay for ATP, we tested this assumption. Surprisingly, although gustatory stimulation mobilizes Ca2+ in taste Receptor (Type II) cells from DKO mice, as from wild type (WT) mice, taste cells from DKO mice fail to release ATP when stimulated with tastants. ATP release could be elicited by depolarizing DKO Receptor cells with KCl, suggesting that ATP-release machinery remains functional in DKO taste buds. To explore the difference in ATP release across genotypes, we employed reverse transcriptase (RT)-PCR, immunostaining, and histochemistry for key proteins underlying ATP secretion and degradation: Pannexin1, TRPM5, and NTPDase2 (ecto-ATPase) are indistinguishable between WT and DKO mice. The ultrastructure of contacts between taste cells and nerve fibers is also normal in the DKO mice. Finally, quantitative RT-PCR show that P2X4 and P2X7, potential modulators of ATP secretion, are similarly expressed in taste buds in WT and DKO taste buds. Importantly, we find that P2X2 is expressed in WT taste buds and appears to function as an autocrine, positive feedback signal to amplify taste-evoked ATP secretion. PMID:21940456

  16. P2X purinoceptors as a link between hyperexcitability and neuroinflammation in status epilepticus.

    Science.gov (United States)

    Henshall, David C; Engel, Tobias

    2015-08-01

    There remains a need for more efficacious treatments for status epilepticus. Prolonged seizures result in the release of ATP from cells which activates the P2 class of ionotropic and metabotropic purinoceptors. The P2X receptors gate depolarizing sodium and calcium entry and are expressed by both neurons and glia throughout the brain, and a number of subtypes are upregulated after status epilepticus. Recent studies have explored the in vivo effects of targeting ATP-gated P2X receptors in preclinical models of status epilepticus, with particular focus on the P2X7 receptor (P2X7R). The P2X7R mediates microglial activation and the release of the proepileptogenic inflammatory cytokine interleukin 1β. The receptor may also directly modulate neurotransmission and gliotransmission and promote the recruitment of immune cells into brain parenchyma. Data from our group and collaborators show that status epilepticus produced by intraamygdala microinjection of kainic acid increases P2X7R expression in the hippocampus and neocortex of mice. Antagonism of the P2X7R in the model reduced seizure severity, microglial activation and interleukin 1β release, and neuronal injury. Coadministration of a P2X7R antagonist with a benzodiazepine also provided seizure suppression in a model of drug-refractory status epilepticus when either treatment alone was minimally effective. More recently, we showed that status epilepticus in immature rats is also reduced by P2X7R antagonism. Together, these findings suggest that P2X receptors may be novel targets for seizure control and interruption of neuroinflammation after status epilepticus. This article is part of a Special Issue entitled "Status Epilepticus". Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Knocking out P2X receptors reduces transmitter secretion in taste buds.

    Science.gov (United States)

    Huang, Yijen A; Stone, Leslie M; Pereira, Elizabeth; Yang, Ruibiao; Kinnamon, John C; Dvoryanchikov, Gennady; Chaudhari, Nirupa; Finger, Thomas E; Kinnamon, Sue C; Roper, Stephen D

    2011-09-21

    In response to gustatory stimulation, taste bud cells release a transmitter, ATP, that activates P2X2 and P2X3 receptors on gustatory afferent fibers. Taste behavior and gustatory neural responses are largely abolished in mice lacking P2X2 and P2X3 receptors [P2X2 and P2X3 double knock-out (DKO) mice]. The assumption has been that eliminating P2X2 and P2X3 receptors only removes postsynaptic targets but that transmitter secretion in mice is normal. Using functional imaging, ATP biosensor cells, and a cell-free assay for ATP, we tested this assumption. Surprisingly, although gustatory stimulation mobilizes Ca(2+) in taste Receptor (Type II) cells from DKO mice, as from wild-type (WT) mice, taste cells from DKO mice fail to release ATP when stimulated with tastants. ATP release could be elicited by depolarizing DKO Receptor cells with KCl, suggesting that ATP-release machinery remains functional in DKO taste buds. To explore the difference in ATP release across genotypes, we used reverse transcriptase (RT)-PCR, immunostaining, and histochemistry for key proteins underlying ATP secretion and degradation: Pannexin1, TRPM5, and NTPDase2 (ecto-ATPase) are indistinguishable between WT and DKO mice. The ultrastructure of contacts between taste cells and nerve fibers is also normal in the DKO mice. Finally, quantitative RT-PCR show that P2X4 and P2X7, potential modulators of ATP secretion, are similarly expressed in taste buds in WT and DKO taste buds. Importantly, we find that P2X2 is expressed in WT taste buds and appears to function as an autocrine, positive feedback signal to amplify taste-evoked ATP secretion.

  18. Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

    International Nuclear Information System (INIS)

    Yang, Yingbin; Cai, Shaoxi; Yang, Li; Yu, Shuhui; Jiang, Jiahuan; Yan, Xiaoqing; Zhang, Haoxing; Liu, Lan; Liu, Qun; Du, Jun; Cai, Shaohui; Sung, K.L. Paul

    2010-01-01

    Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

  19. Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yingbin [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); School of Life Science, Southwest University, Chongqing 400715 (China); Cai, Shaoxi, E-mail: sxcai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Yang, Li [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); College of Pharmacy, Jinan University, Guangzhou 510632 (China); Yu, Shuhui [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Library of Southwest University, Chongqing 400715 (China); Jiang, Jiahuan; Yan, Xiaoqing [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Zhang, Haoxing [School of Life Science, Southwest University, Chongqing 400715 (China); Liu, Lan [Department of Laboratory of Medicine, Children' s Hospital of Chongqin Medical University, Chongqing 400014 (China); Liu, Qun [College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041 (China); Du, Jun [Center of Microbiology, Biochemistry, and Pharmacology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou 510080 (China); Cai, Shaohui [College of Pharmacy, Jinan University, Guangzhou 510632 (China); Sung, K.L. Paul [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Departments of Orthopaedic Surgery and Bioengineering, University of California, SD 0412 (United States)

    2010-12-10

    Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

  20. Evaluating Application-Layer Traffic Optimization Cost Metrics for P2P Multimedia Streaming

    DEFF Research Database (Denmark)

    Poderys, Justas; Soler, José

    2017-01-01

    To help users of P2P communication systems perform better-than-random selection of communication peers, Internet Engineering Task Force standardized the Application Layer Traffic Optimization (ALTO) protocol. The ALTO provided data-routing cost metric, can be used to rank peers in P2P communicati...

  1. P2P XQuery and the StreetTiVo application

    NARCIS (Netherlands)

    P.A. Boncz (Peter); Y. Zhang (Ying)

    2007-01-01

    textabstractIn the AmbientDB project, we are building MonetDB/XQuery, an open-source XML DBMS (XDBMS) with support for distributed querying and P2P services. Our work is motivated by the hypothesis that P2P is a disruptive paradigm that should change the nature of database technology. Most of the

  2. Rare missense mutations in P2RY11 in narcolepsy with cataplexy

    DEFF Research Database (Denmark)

    Degn, Matilda; Dauvilliers, Yves; Dreisig, Karin

    2017-01-01

    these are single nucleotide polymorphisms in the P2RY11-EIF3G locus. It is unknown how these genetic variants affect narcolepsy pathogenesis and whether the effect is directly related to P2Y11 signalling or EIF3G function. Exome sequencing in 18 families with at least two affected narcolepsy with cataplexy...

  3. On the non-existence of orthogonal instanton bundles on P^{2n+1}

    Directory of Open Access Journals (Sweden)

    Łucja Farnik

    2009-11-01

    Full Text Available In this paper we prove that there do not exist orthogonal instanton bundles on P^{2n+1} . In order to demonstrate this fact, we propose a new way of representing the invariant, introduced by L. Costa and G. Ottaviani, related to a rank 2n instanton bundle on P^{2n+1}.

  4. Nociceptive transmission and modulation via P2X receptors in central pain syndrome.

    Science.gov (United States)

    Kuan, Yung-Hui; Shyu, Bai-Chuang

    2016-05-26

    Painful sensations are some of the most frequent complaints of patients who are admitted to local medical clinics. Persistent pain varies according to its causes, often resulting from local tissue damage or inflammation. Central somatosensory pathway lesions that are not adequately relieved can consequently cause central pain syndrome or central neuropathic pain. Research on the molecular mechanisms that underlie this pathogenesis is important for treating such pain. To date, evidence suggests the involvement of ion channels, including adenosine triphosphate (ATP)-gated cation channel P2X receptors, in central nervous system pain transmission and persistent modulation upon and following the occurrence of neuropathic pain. Several P2X receptor subtypes, including P2X2, P2X3, P2X4, and P2X7, have been shown to play diverse roles in the pathogenesis of central pain including the mediation of fast transmission in the peripheral nervous system and modulation of neuronal activity in the central nervous system. This review article highlights the role of the P2X family of ATP receptors in the pathogenesis of central neuropathic pain and pain transmission. We discuss basic research that may be translated to clinical application, suggesting that P2X receptors may be treatment targets for central pain syndrome.

  5. Analytical Model for Mesh-based P2PVoD

    NARCIS (Netherlands)

    Lu, Y.; Mol, J.D.D.; Kuipers, F.A.; Van Mieghem, P.

    Recently, there has been a growing interest in academic and commercial environments for Video-on-Demand (VoD) using Peer-to-Peer (P2P) technology. Unlike centralized solutions for VoD services, P2P technology lets the clients distribute video content among themselves. In this paper, we propose an

  6. Characterization of fatty acid binding by the P2 myelin protein

    International Nuclear Information System (INIS)

    Gudaitis, P.G.; Weise, M.J.

    1987-01-01

    In recent years, significant sequence homology has been found between the P2 protein of peripheral myelin and intracellular retinoid- and fatty acid-binding proteins. They have found that salt extracts of bovine intradural nerve roots contain the P2 basic protein in association with free fatty acid. Preliminary results from quantitative analyses showed a ratio of 0.4-1.1 fatty acid (mainly oleate and palmitate) per P2 molecule. P2/ligand interactions were partially characterized using ( 3 H)-oleate in gel permeation assays and binding studies using lipidex to separated bound and free fatty acid. Methyloleate was found to displace ( 3 H)-oleate from P2, indicating that ligand binding interactions are predominantly hydrophobic in nature. On the other hand, myristic acid and retinol did not inhibit the binding of oleate to the protein, results consistent with a decided affinity for long chain fatty acids but not for the retinoids. The binding between P2 and oleic acid showed an apparent Kd in the micromolar range, a value comparable to those found for other fatty acid-binding proteins. From these results they conclude that P2 shares not only structural homology with certain fatty acid binding proteins but also an ability to bind long chain fatty acids. Although the significance of these similarities is not yet clear, they may, by analogy, expect P2 to have a role in PNS lipid metabolism

  7. Bone turnover is altered in transgenic rats overexpressing the P2Y2 purinergic receptor

    DEFF Research Database (Denmark)

    Ellegaard, Maria; Agca, Cansu; Petersen, Solveig

    2017-01-01

    overexpression on bone status and bone cell function using a transgenic rat. Three-month-old female transgenic Sprague Dawley rats overexpressing P2Y2R (P2Y2R-Tg) showed higher bone strength of the femoral neck. Histomorphometry showed increase in resorptive surfaces and reduction in mineralizing surfaces. Both...

  8. Personalised Peer-Supported Learning: The Peer-to-Peer Learning Environment (P2PLE)

    Science.gov (United States)

    Corneli, Joseph; Mikroyannidis, Alexander

    2011-01-01

    The Peer-to-Peer Learning Environment (P2PLE) is a proposed approach to helping learners co-construct their learning environment using recommendations about people, content, and tools. The work draws on current research on PLEs, and participant observation at the Peer-to-Peer University (P2PU). We are particularly interested in ways of eliciting…

  9. Assignment of two new host range types to the P2 family of temperate coliphages.

    Science.gov (United States)

    Poon, A P; Dhillon, T S

    1986-04-01

    Six non-inducible coliphages which grow on Escherichia coli C but not on K12 (C-specific) were shown to be antigenically related to P2. All six were shown to be P4 helpers and some of them could also recombine with P2.

  10. Excitation functions of the (pn) and (p,2n) reactions on Cd isotopes. [(pn) and (p,2n) reactions on the sup(110-114,116)Cd

    Energy Technology Data Exchange (ETDEWEB)

    Skakun, E A; Klyucharev, A P; Rakivnenko, Yu N; Romanij, I A [AN Ukrainskoi SSR, Kiev. Fiziko-Tekhnicheskii Inst.

    1975-01-01

    Excitation functions of (pn)- and (p,2n)-reactions on /sup 110/-/sup 114/,/sup 116/Cd nuclei are measured in a range of incident proton energy up to 20 MeV. Experimental results are compared to calculated ones.

  11. Convergence of Internet and TV: The Commercial Viability of P2P Content Delivery

    Science.gov (United States)

    de Boever, Jorn

    The popularity of (illegal) P2P (peer-to-peer) file sharing has a disruptive impact on Internet traffic and business models of content providers. In addition, several studies have found an increasing demand for bandwidth consuming content, such as video, on the Internet. Although P2P systems have been put forward as a scalable and inexpensive model to deliver such content, there has been relatively little economic analysis of the potentials and obstacles of P2P systems as a legal and commercial content distribution model. Many content providers encounter uncertainties regarding the adoption or rejection of P2P networks to spread content over the Internet. The recent launch of several commercial, legal P2P content distribution platforms increases the importance of an integrated analysis of the Strengths, Weaknesses, Opportunities and Threats (SWOT).

  12. Fuzzy-rule-based Adaptive Resource Control for Information Sharing in P2P Networks

    Science.gov (United States)

    Wu, Zhengping; Wu, Hao

    With more and more peer-to-peer (P2P) technologies available for online collaboration and information sharing, people can launch more and more collaborative work in online social networks with friends, colleagues, and even strangers. Without face-to-face interactions, the question of who can be trusted and then share information with becomes a big concern of a user in these online social networks. This paper introduces an adaptive control service using fuzzy logic in preference definition for P2P information sharing control, and designs a novel decision-making mechanism using formal fuzzy rules and reasoning mechanisms adjusting P2P information sharing status following individual users' preferences. Applications of this adaptive control service into different information sharing environments show that this service can provide a convenient and accurate P2P information sharing control for individual users in P2P networks.

  13. P2X receptors as targets for the treatment of status epilepticus

    Science.gov (United States)

    Henshall, David C.; Diaz-Hernandez, Miguel; Miras-Portugal, M. Teresa; Engel, Tobias

    2013-01-01

    Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA) transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4, and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection. PMID:24324404

  14. Effective role of CaO/P2O5 ratio on SiO2-CaO-P2O5 glass system

    Directory of Open Access Journals (Sweden)

    P. Kiran

    2017-05-01

    Full Text Available In the present work, the effect of the CaO/P2O5 ratio on the composition of sol-gel synthesized 58SiO2-(19 − xP2O5–(23 + xCaO (x = 0, 5, 10 and 15 mol% glass samples was studied. Further, the effect of NBO/BO ratio on hydroxy carbonated apatite layer (HCA forming ability based on dissolution behavior in simulated body fluid (SBF solution was also investigated. CaO/P2O5 ratios of synthesized glass samples were 1.2, 2, 3.6, and 9.5, respectively. NBO/BO ratios were obtained using Raman spectroscopic analysis as 0.58, 1.20, 1.46, and 1.78, respectively. All samples were soaked in the SBF solution for 7 days. The calculated weight losses of these samples were 58%, 64%, 83%, and 89% for corresponding NBO/BO ratios. The increase in CaO/P2O5 ratio increases the NBO/BO ratios. However, the increase in NBO/BO ratio increases HCA forming ability of SBF treated samples. The HCA crystalline layer formation was confirmed through X-ray Diffraction (XRD, Transmission Electron Microscopy (TEM, Scanning Electron Microscopy (SEM, Raman and Infrared spectroscopic analysis. Higher CaO/P2O5 ratio favors the increase in HCA formation for SBF treated calcium phospho silicate glasses.

  15. The platelet P2Y(12) receptor under normal and pathological conditions. Assessment with the radiolabeled selective antagonist [(3)H]PSB-0413.

    Science.gov (United States)

    Ohlmann, Philippe; Lecchi, Anna; El-Tayeb, Ali; Müller, Christa E; Cattaneo, Marco; Gachet, Christian

    2013-03-01

    Various radioligands have been used to characterize and quantify the platelet P2Y(12) receptor, which share several weaknesses: (a) they are metabolically unstable and substrates for ectoenzymes, (b) they are agonists, and (c) they do not discriminate between P2Y(1) and P2Y(12). We used the [(3)H]PSB-0413 selective P2Y(12) receptor antagonist radioligand to reevaluate the number of P2Y(12) receptors in intact platelets and in membrane preparations. Studies in humans showed that: (1) [(3)H]PSB-0413 bound to 425 ± 50 sites/platelet (K (D) = 3.3 ± 0.6 nM), (2) 0.5 ± 0.2 pmol [(3)H]PSB-0413 bound to 1 mg protein of platelet membranes (K (D) = 6.5 ± 3.6 nM), and (3) competition studies confirmed the known features of P2Y(12), with the expected rank order of potency: AR-C69931MX > 2MeSADP ≫ ADPβS > ADP, while the P2Y(1) ligand MRS2179 and the P2X(1) ligand α,β-Met-ATP did not displace [(3)H]PSB-0413 binding. Patients with severe P2Y(12) deficiency displayed virtually no binding of [(3)H]PSB-0413 to intact platelets, while a patient with a dysfunctional P2Y(12) receptor had normal binding. Studies in mice showed that: (1) [(3)H]PSB-0413 bound to 634 ± 87 sites/platelet (K (D) = 14 ± 4.5 nM) and (2) 0.7 pmol ± 0.3 [(3)H]PSB-0413 bound to 1 mg protein of platelet membranes (K (D) = 9.1 ± 5.3 nM). Clopidogrel and other thiol reagents like pCMBS or DTT abolished the binding both to intact platelets and membrane preparations. Therefore, [(3)H]PSB-0413 is an accurate and selective tool for radioligand binding studies aimed at quantifying P2Y(12) receptors, to identify patients with P2Y(12) deficiencies or quantify the effect of P2Y(12) targeting drugs.

  16. Cooverexpression of EpCAM and c-myc genes in malignant breast ...

    Indian Academy of Sciences (India)

    using SDS/PAGE and transferred to a nitrocellulose mem- brane in a condition of 100 V for 90 min at 4. ◦. C. Block- ing of membranes was done in blocking solution (5% nonfat milk powder, in TBST) at room temperature for 1 h followed by the incubation of membranes with the anti-EpCAM anti- body (5% nonfat milk powder, ...

  17. Treatment of Endocrine-Resistant Breast Cancer with a Small Molecule c-Myc Inhibitor

    Science.gov (United States)

    2016-08-01

    Selective inhibition of tu- mor oncogenes by disruption of super-enhancers. Cell 2013; 153:320-334. 26 Ott CJ, Kopp N, Bird L, et al. BET bromodomain...maintenance of nor- mal functions of the female reproductive tissues and non-repro- ductive tissues including metabolic homeostasis, skeletal...steroid/thyroid receptor superfamily members. Annu Rev Biochem 1994;63:451–86. [2] Della Torre S, Benedusi V, Fontana R, Maggi A. Energy metabolism and

  18. Cooverexpression of EpCAM and c-myc genes in malignant breast ...

    Indian Academy of Sciences (India)

    SAMIRA SADEGHI

    catumaxomab, an efficient monoclonal antibody approved in. European Market in 2009, to reduce the rate of metastasis in patients with metastatic breast cancer. ..... + tumours. However, a broader study is required to assess this hypothesis.

  19. Cooverexpression of EpCAM and c-myc genes in malignant breast ...

    Indian Academy of Sciences (India)

    RT-qPCR method, our results showed that EpCAM was overexpressed in 48% of malignant and 11.1% of benign .... to 45% of patients with breast cancer in different studies ..... in cancer maintenance, development, drug resistance, as well.

  20. Cooverexpression of EpCAM and c-myc genes in malignant breast ...

    Indian Academy of Sciences (India)

    SAMIRA SADEGHI

    Samira Sadeghi et al. domain protein2), and the transcription factor Lef1 that is ... antibody approved in. European Market in 2009, to reduce the rate of metastasis in .... Real-Time PCR. System and Maxima SYBR Green/ROX qPCR Master Mix.

  1. The c-myc oncoprotein forms a specific complex with the product of the retinoblastoma gene

    NARCIS (Netherlands)

    Bernards, R.A.; Rustgi, A.K.; Dyson, N.; Hill, D.

    1991-01-01

    Myc proteins are involved in the regulation of cell proliferation and differentiation. Deregulated expression of myc family genes has been implicated in the genesis of a variety of cancers. Myc proteins share significant sequence homology in the carboxyl terminus with a number of

  2. RESEARCH ARTICLE Co-overexpression of EpCAM and c-myc ...

    Indian Academy of Sciences (India)

    Purpose:The overexpression of epithelial cell adhesion molecule (EpCAM) ... Half LIM domain protein2), and the transcription factor Lef1 that is cleaved by presenilin-2 ..... and self-renewal capability, producing a rapidly dividing tumor mass.

  3. Localization of specific sequences and DNA single-strand breaks in individual UV-A-irradiated human lymphocytes by COMET FISH

    Science.gov (United States)

    Bock, Claudia; Rapp, Alexander; Dittmar, Heike; Monajembashi, Shamci; Greulich, Karl-Otto

    1999-01-01

    The COMET assay, a single cell electrophoresis technique which allows to separate electrophoretically fractionated DNA according to size has been combined with fluorescence in situ hybridization (FISH) which allows to localize specific genes or gene regions. This combination (COMET FISH) allows the detection of DNA single strand breaks in specific regions of the genome of human lymphocytes at the single cell level. Various types of DNA probes, e.g. centromere-, (alpha) - satellite-, telomere-, whole chromosome-, single copy- and region specific DNA probes have been used to investigate whether the UV-A induced DNA single strand breaks are distributed randomly all over the human genome or induced at specific sites ('hot spots'). In the investigated human peripheral blood lymphocytes all but one centromere reveal low sensitivity for UV-A irradiation (500 kJ/m2), while telomeres are randomly distributed over COMET heads and tails. The human chromosome 1 is fractionated by irradiation, but remains in the COMET head, indicating an only moderate degree of fractionation. Among three tested single copy probes, c- myc, p53 and p58, the p53 gene located on chromosome 17p13.1 and the p58 gene (1p36) appear to be located in UV-A stable regions of the human genome in 95% of 65 investigated lymphocytes. In contrast, the c-myc proto-oncogene (8q24) is found in the COMET tail in 90% of the 27 investigated lymphocytes and thus appears to be more sensitive to UV-A irradiation.

  4. Lack of the purinergic receptor P2X7 results in resistance to contact hypersensitivity

    Science.gov (United States)

    Weber, Felix C.; Esser, Philipp R.; Müller, Tobias; Ganesan, Jayanthi; Pellegatti, Patrizia; Simon, Markus M.; Zeiser, Robert; Idzko, Marco; Jakob, Thilo

    2010-01-01

    Sensitization to contact allergens requires activation of the innate immune system by endogenous danger signals. However, the mechanisms through which contact allergens activate innate signaling pathways are incompletely understood. In this study, we demonstrate that mice lacking the adenosine triphosphate (ATP) receptor P2X7 are resistant to contact hypersensitivity (CHS). P2X7-deficient dendritic cells fail to induce sensitization to contact allergens and do not release IL-1β in response to lipopolysaccharide (LPS) and ATP. These defects are restored by pretreatment with LPS and alum in an NLRP3- and ASC-dependent manner. Whereas pretreatment of wild-type mice with P2X7 antagonists, the ATP-degrading enzyme apyrase or IL-1 receptor antagonist, prevents CHS, IL-1β injection restores CHS in P2X7-deficient mice. Thus, P2X7 is a crucial receptor for extracellular ATP released in skin in response to contact allergens. The lack of P2X7 triggering prevents IL-1β release, which is an essential step in the sensitization process. Interference with P2X7 signaling may be a promising strategy for the prevention of allergic contact dermatitis. PMID:21059855

  5. Rab5 regulates internalisation of P2X4 receptors and potentiation by ivermectin.

    Science.gov (United States)

    Stokes, Leanne

    2013-03-01

    The P2X4 receptor is an ATP-gated ion channel expressed in neurons, endothelia and immune cells. Plasma membrane expression of P2X4 is regulated by dynamin-dependent endocytosis, and this study identifies a Rab5-dependent pathway of receptor internalisation. Expression of Rab5 constructs altered the distribution of P2X4 in HEK-293 cells, and both constitutive internalisation and agonist-induced desensitisation of P2X4 were increased by co-expression of wild-type Rab5 or constitutively active Rab5 (Q79L). Expression of inactive dynamin K44A and Rab5 S34N constructs abolished agonist-induced desensitisation, suggesting internalisation as the underlying mechanism. Blocking P2X4 internalisation in this way also abolished potentiation of ATP-induced currents by the allosteric modulator ivermectin. This suggests that the dynamin-Rab5 internalisation pathway is essential for the ivermectin potentiation effect. In agreement with this hypothesis, the co-expression of wild-type dynamin, wild-type Rab5 or active Rab5 (Q79L) could increase the potentiation of the ATP-induced P2X4 response by ivermectin. These findings highlight Rab5 GTPase as a key regulator of P2X4 receptor cell surface expression and internalisation.

  6. Blockade of P2X7 receptors or pannexin-1 channels similarly attenuates postischemic damage.

    Science.gov (United States)

    Cisneros-Mejorado, Abraham; Gottlieb, Miroslav; Cavaliere, Fabio; Magnus, Tim; Koch-Nolte, Friederich; Scemes, Eliana; Pérez-Samartín, Alberto; Matute, Carlos

    2015-05-01

    The role of P2X7 receptors and pannexin-1 channels in ischemic damage remains controversial. Here, we analyzed their contribution to postanoxic depolarization after ischemia in cultured neurons and in brain slices. We observed that pharmacological blockade of P2X7 receptors or pannexin-1 channels delayed the onset of postanoxic currents and reduced their slope, and that simultaneous inhibition did not further enhance the effects of blocking either one. These results were confirmed in acute cortical slices from P2X7 and pannexin-1 knockout mice. Oxygen-glucose deprivation in cortical organotypic cultures caused neuronal death that was reduced with P2X7 and pannexin-1 blockers as well as in organotypic cultures derived from mice lacking P2X7 and pannexin 1. Subsequently, we used transient middle cerebral artery occlusion to monitor the neuroprotective effect of those drugs in vivo. We found that P2X7 and pannexin-1 antagonists, and their ablation in knockout mice, substantially attenuated the motor symptoms and reduced the infarct volume to ~50% of that in vehicle-treated or wild-type animals. These results show that P2X7 receptors and pannexin-1 channels are major mediators of postanoxic depolarization in neurons and of brain damage after ischemia, and that they operate in the same deleterious signaling cascade leading to neuronal and tissue demise.

  7. Bandwidth Reduction via Localized Peer-to-Peer (P2P Video

    Directory of Open Access Journals (Sweden)

    Ken Kerpez

    2010-01-01

    Full Text Available This paper presents recent research into P2P distribution of video that can be highly localized, preferably sharing content among users on the same access network and Central Office (CO. Models of video demand and localized P2P serving areas are presented. Detailed simulations of passive optical networks (PON are run, and these generate statistics of P2P video localization. Next-Generation PON (NG-PON is shown to fully enable P2P video localization, but the lower rates of Gigabit-PON (GPON restrict performance. Results here show that nearly all of the traffic volume of unicast video could be delivered via localized P2P. Strong growth in video delivery via localized P2P could lower overall future aggregation and core network bandwidth of IP video traffic by 58.2%, and total consumer Internet traffic by 43.5%. This assumes aggressive adoption of technologies and business practices that enable highly localized P2P video.

  8. Orientation of Zn3P2 films via phosphidation of Zn precursors

    Science.gov (United States)

    Katsube, Ryoji; Nose, Yoshitaro

    2017-02-01

    Orientation of solar absorber is an important factor to achieve high efficiency of thin film solar cells. In the case of Zn3P2 which is a promising absorber of low-cost and high-efficiency solar cells, (110)/(001) orientation was only reported in previous studies. We have successfully prepared (101)-oriented Zn3P2 films by phosphidation of (0001)-oriented Zn films at 350 °C. The phosphidation mechanism of Zn is discussed through STEM observations on the partially-reacted sample and the consideration of the relationship between the crystal structures of Zn and Zn3P2 . We revealed that (0001)-oriented Zn led to nucleation of (101)-oriented Zn3P2 due to the similarity in atomic arrangement between Zn and Zn3P2 . The electrical resistivity of the (101)-oriented Zn3P2 film was lower than those of (110)/(001)-oriented films, which is an advantage of the phosphidation technique to the growth processes in previous works. The results in this study demonstrated that well-conductive Zn3P2 films could be obtained by controlling orientations of crystal grains, and provide a guiding principle for microstructure control in absorber materials.

  9. Impaired P2X signalling pathways in renal microvascular myocytes in genetic hypertension

    KAUST Repository

    Gordienko, Dmitri V.; Povstyan, Oleksandr V.; Sukhanova, Khrystyna Yu; Raphaë l, Maylis; Harhun, Maksym I.; Dyskina, Yulia; Lehen'Kyi, V'Yacheslav; Jama, Abdirahman Mahmoud; Lu, Zhiliang; Skryma, Roman N.; Prevarskaya, Natalia B.

    2014-01-01

    Aims P2X receptors (P2XRs) mediate sympathetic control and autoregulation of renal circulation triggering preglomerular vasoconstriction, which protects glomeruli from elevated pressures. Although previous studies established a casual link between glomerular susceptibility to hypertensive injury and decreased preglomerular vascular reactivity to P2XR activation, the mechanisms of attenuation of the P2XR signalling in hypertension remained unknown. We aimed to analyse molecular mechanisms of the impairment of P2XR signalling in renal vascular smooth muscle cells (RVSMCs) in genetic hypertension. Methods and results We compared the expression of pertinent genes and P2XR-linked Ca2+ entry and Ca2+ release mechanisms in RVSMCs of spontaneously hypertensive rats (SHRs) and their normotensive controls, Wistar Kyoto (WKY) rats. We found that, in SHR RVSMCs, P2XR-linked Ca2+ entry and Ca2+ release from the sarcoplasmic reticulum (SR) are both significantly reduced. The former is due to down-regulation of the P2X1 subunit. The latter is caused by a decrease of the SR Ca2+ load. The SR Ca2+ load reduction is caused by attenuated Ca2+ uptake via down-regulated sarco-/endoplasmic reticulum Ca2+-ATPase 2b and elevated Ca2+ leak from the SR via ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors. Spontaneous activity of these Ca2+-release channels is augmented due to up-regulation of RyR type 2 and elevated IP3 production by up-regulated phospholipase C-β1. Conclusions Our study unravels the cellular and molecular mechanisms of attenuation of P2XR-mediated preglomerular vasoconstriction that elevates glomerular susceptibility to harmful hypertensive pressures. This provides an important impetus towards understanding of the pathology of hypertensive renal injury.

  10. P2X7 Receptors Drive Spine Synapse Plasticity in the Learned Helplessness Model of Depression.

    Science.gov (United States)

    Otrokocsi, Lilla; Kittel, Ágnes; Sperlágh, Beáta

    2017-10-01

    Major depressive disorder is characterized by structural and functional abnormalities of cortical and limbic brain areas, including a decrease in spine synapse number in the dentate gyrus of the hippocampus. Recent studies highlighted that both genetic and pharmacological invalidation of the purinergic P2X7 receptor (P2rx7) leads to antidepressant-like phenotype in animal experiments; however, the impact of P2rx7 on depression-related structural changes in the hippocampus is not clarified yet. Effects of genetic deletion of P2rx7s on depressive-like behavior and spine synapse density in the dentate gyrus were investigated using the learned helplessness mouse model of depression. We demonstrate that in wild-type animals, inescapable footshocks lead to learned helplessness behavior reflected in increased latency and number of escape failures to subsequent escapable footshocks. This behavior is accompanied with downregulation of mRNA encoding P2rx7 and decrease of spine synapse density in the dentate gyrus as determined by electron microscopic stereology. In addition, a decrease in synaptopodin but not in PSD95 and NR2B/GluN2B protein level was also observed under these conditions. Whereas the absence of P2rx7 was characterized by escape deficit, no learned helpless behavior is observed in these animals. Likewise, no decrease in spine synapse number and synaptopodin protein levels was detected in response to inescapable footshocks in P2rx7-deficient animals. Our findings suggest the endogenous activation of P2rx7s in the learned helplessness model of depression and decreased plasticity of spine synapses in P2rx7-deficient mice might explain the resistance of these animals to repeated stressful stimuli. © The Author 2017. Published by Oxford University Press on behalf of CINP.

  11. Interaction of GABAA receptors with purinergic P2X2 receptors

    International Nuclear Information System (INIS)

    Shrivastava, A.

    2010-01-01

    GABA A Rs in the spinal cord are evolving as an important target for drug development against pain. Purinergic P2X 2 Rs are also expressed in spinal cord neurons and are known to cross-talk with GABA A Rs. Here we investigated a possible 'dynamic' interaction between GABA A Rs and P2X 2 Rs using co-immunoprecipitation and FRET studies in HEK cells along with co-localization and single particle tracking studies in spinal cord neurons. Our results suggest that a significant proportion of P2X 2 Rs forms a transient complex with GABA A Rs inside the cell, thus stabilizing these receptors and using them for co-trafficking to the cell surface. P2X 2 Rs and GABA A Rs are then co-inserted into the cell membrane and are primarily located extra-synaptically. Furthermore, agonist induced activation of P2X 2 Rs results in disassembly of the receptor complex and destabilization of GABA A Rs whereas P2X 2 Rs are stabilized and form larger clusters. Antagonist-induced blocking of P2XRs results in co-stabilization of this receptor complex at the cell surface. These results suggest a novel mechanism where association of P2XRs with other receptors could be used for specific targeting to the neuronal membrane, thus providing an extrasynaptic receptor reserve that could regulate the excitability of neurons. We further conclude that blocking the excitatory activity of excessively released ATP under diseased state by P2XR antagonists could simultaneously enhance synaptic inhibition mediated by GABA A Rs.(author) (author) [de

  12. Impaired P2X signalling pathways in renal microvascular myocytes in genetic hypertension

    KAUST Repository

    Gordienko, Dmitri V.

    2014-12-16

    Aims P2X receptors (P2XRs) mediate sympathetic control and autoregulation of renal circulation triggering preglomerular vasoconstriction, which protects glomeruli from elevated pressures. Although previous studies established a casual link between glomerular susceptibility to hypertensive injury and decreased preglomerular vascular reactivity to P2XR activation, the mechanisms of attenuation of the P2XR signalling in hypertension remained unknown. We aimed to analyse molecular mechanisms of the impairment of P2XR signalling in renal vascular smooth muscle cells (RVSMCs) in genetic hypertension. Methods and results We compared the expression of pertinent genes and P2XR-linked Ca2+ entry and Ca2+ release mechanisms in RVSMCs of spontaneously hypertensive rats (SHRs) and their normotensive controls, Wistar Kyoto (WKY) rats. We found that, in SHR RVSMCs, P2XR-linked Ca2+ entry and Ca2+ release from the sarcoplasmic reticulum (SR) are both significantly reduced. The former is due to down-regulation of the P2X1 subunit. The latter is caused by a decrease of the SR Ca2+ load. The SR Ca2+ load reduction is caused by attenuated Ca2+ uptake via down-regulated sarco-/endoplasmic reticulum Ca2+-ATPase 2b and elevated Ca2+ leak from the SR via ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors. Spontaneous activity of these Ca2+-release channels is augmented due to up-regulation of RyR type 2 and elevated IP3 production by up-regulated phospholipase C-β1. Conclusions Our study unravels the cellular and molecular mechanisms of attenuation of P2XR-mediated preglomerular vasoconstriction that elevates glomerular susceptibility to harmful hypertensive pressures. This provides an important impetus towards understanding of the pathology of hypertensive renal injury.

  13. Expression analysis of the speech-related genes FoxP1 and FoxP2 and their relation to singing behavior in two songbird species

    Science.gov (United States)

    Chen, Qianqian; Heston, Jonathan B.; Burkett, Zachary D.; White, Stephanie A.

    2013-01-01

    SUMMARY Humans and songbirds are among the rare animal groups that exhibit socially learned vocalizations: speech and song, respectively. These vocal-learning capacities share a reliance on audition and cortico-basal ganglia circuitry, as well as neurogenetic mechanisms. Notably, the transcription factors Forkhead box proteins 1 and 2 (FoxP1, FoxP2) exhibit similar expression patterns in the cortex and basal ganglia of humans and the zebra finch species of songbird, among other brain regions. Mutations in either gene are associated with language disorders in humans. Experimental knock-down of FoxP2 in the basal ganglia song control region Area X during song development leads to imprecise copying of tutor songs. Moreover, FoxP2 levels decrease naturally within Area X when zebra finches sing. Here, we examined neural expression patterns of FoxP1 and FoxP2 mRNA in adult Bengalese finches, a songbird species whose songs exhibit greater sequence complexity and increased reliance on audition for maintaining their quality. We found that FoxP1 and FoxP2 expression in Bengalese finches is similar to that in zebra finches, including strong mRNA signals for both factors in multiple song control nuclei and enhancement of FoxP1 in these regions relative to surrounding brain tissue. As with zebra finches, when Bengalese finches sing, FoxP2 is behaviorally downregulated within basal ganglia Area X over a similar time course, and expression negatively correlates with the amount of singing. This study confirms that in multiple songbird species, FoxP1 expression highlights song control regions, and regulation of FoxP2 is associated with motor control of song. PMID:24006346

  14. Modulation of Central Synapses by Astrocyte-Released ATP and Postsynaptic P2X Receptors

    Science.gov (United States)

    Pankratov, Yuriy

    2017-01-01

    Communication between neuronal and glial cells is important for neural plasticity. P2X receptors are ATP-gated cation channels widely expressed in the brain where they mediate action of extracellular ATP released by neurons and/or glia. Recent data show that postsynaptic P2X receptors underlie slow neuromodulatory actions rather than fast synaptic transmission at brain synapses. Here, we review these findings with a particular focus on the release of ATP by astrocytes and the diversity of postsynaptic P2X-mediated modulation of synaptic strength and plasticity in the CNS. PMID:28845311

  15. A Simple FSPN Model of P2P Live Video Streaming System

    OpenAIRE

    Kotevski, Zoran; Mitrevski, Pece

    2011-01-01

    Peer to Peer (P2P) live streaming is relatively new paradigm that aims at streaming live video to large number of clients at low cost. Many such applications already exist in the market, but, prior to creating such system it is necessary to analyze its performance via representative model that can provide good insight in the system’s behavior. Modeling and performance analysis of P2P live video streaming systems is challenging task which requires addressing many properties and issues of P2P s...

  16. Apical membrane P2Y4 purinergic receptor controls K+ secretion by strial marginal cell epithelium

    Directory of Open Access Journals (Sweden)

    Scofield Margaret A

    2005-11-01

    Full Text Available Abstract Background It was previously shown that K+ secretion by strial marginal cell epithelium is under the control of G-protein coupled receptors of the P2Y family in the apical membrane. Receptor activation by uracil nucleotides (P2Y2, P2Y4 or P2Y6 leads to a decrease in the electrogenic K+ secretion. The present study was conducted to determine the subtype of the functional purinergic receptor in gerbil stria vascularis, to test if receptor activation leads to elevation of intracellular [Ca2+] and to test if the response to these receptors undergoes desensitization. Results The transepithelial short circuit current (Isc represents electrogenic K+ secretion and was found to be decreased by uridine 5'-triphosphate (UTP, adenosine 5'-triphosphate (ATP and diadenosine tetraphosphate (Ap4A but not uridine 5'-diphosphate (UDP at the apical membrane of marginal cells of the gerbil stria vascularis. The potencies of these agonists were consistent with rodent P2Y4 and P2Y2 but not P2Y6 receptors. Activation caused a biphasic increase in intracellular [Ca2+] that could be partially blocked by 2-aminoethoxy-diphenyl borate (2-APB, an inhibitor of the IP3 receptor and store-operated channels. Suramin (100 μM did not inhibit the effect of UTP (1 μM. The ineffectiveness of suramin at the concentration used was consistent with P2Y4 but not P2Y2. Transcripts for both P2Y2 and P2Y4 were found in the stria vascularis. Sustained exposure to ATP or UTP for 15 min caused a depression of Isc that appeared to have two components but with apparently no chronic desensitization. Conclusion The results support the conclusion that regulation of K+ secretion across strial marginal cell epithelium occurs by P2Y4 receptors at the apical membrane. The apparent lack of desensitization of the response is consistent with two processes: a rapid-onset phosphorylation of KCNE1 channel subunit and a slower-onset of regulation by depletion of plasma membrane PIP2.

  17. Modulation of Central Synapses by Astrocyte-Released ATP and Postsynaptic P2X Receptors

    Directory of Open Access Journals (Sweden)

    Eric Boué-Grabot

    2017-01-01

    Full Text Available Communication between neuronal and glial cells is important for neural plasticity. P2X receptors are ATP-gated cation channels widely expressed in the brain where they mediate action of extracellular ATP released by neurons and/or glia. Recent data show that postsynaptic P2X receptors underlie slow neuromodulatory actions rather than fast synaptic transmission at brain synapses. Here, we review these findings with a particular focus on the release of ATP by astrocytes and the diversity of postsynaptic P2X-mediated modulation of synaptic strength and plasticity in the CNS.

  18. Zidovudine ameliorates pathology in the mouse model of Duchenne muscular dystrophy via P2RX7 purinoceptor antagonism.

    Science.gov (United States)

    Al-Khalidi, Rasha; Panicucci, Chiara; Cox, Paul; Chira, Natalia; Róg, Justyna; Young, Christopher N J; McGeehan, Rhiannon E; Ambati, Kameshwari; Ambati, Jayakrishna; Zabłocki, Krzysztof; Gazzerro, Elisabetta; Arkle, Stephen; Bruno, Claudio; Górecki, Dariusz C

    2018-04-11

    Duchenne muscular dystrophy (DMD) is the most common inherited muscle disorder that causes severe disability and death of young men. This disease is characterized by progressive muscle degeneration aggravated by sterile inflammation and is also associated with cognitive impairment and low bone density. Given that no current treatment can improve the long-term outcome, approaches with a strong translational potential are urgently needed. Duchenne muscular dystrophy (DMD) alters P2RX7 signaling in both muscle and inflammatory cells and inhibition of this receptor resulted in a significant attenuation of muscle and non-muscle symptoms in DMD mdx mouse model. As P2RX7 is an attractive target in a range of human diseases, specific antagonists have been developed. Yet, these will require lengthy safety testing in the pediatric population of Duchenne muscular dystrophy (DMD) patients. In contrast, Nucleoside Reverse Transcriptase Inhibitors (NRTIs) can act as P2RX7 antagonists and are drugs with an established safety record, including in children. We demonstrate here that AZT (Zidovudine) inhibits P2RX7 functions acting via the same allosteric site as other antagonists. Moreover, short-term AZT treatment at the peak of disease in DMD mdx mice attenuated the phenotype without any detectable side effects. Recovery was evident in the key parameters such as reduced sarcolemma permeability confirmed by lower serum creatine kinase levels and IgG influx into myofibres, decreased inflammatory cell numbers and inflammation markers in leg and heart muscles of treated mice. Moreover, this short-term therapy had some positive impact on muscle strength in vivo and no detrimental effect on mitochondria, which is the main side-effect of Nucleoside Reverse Transcriptase Inhibitors (NRTIs). Given these results, we postulate that AZT could be quickly re-purposed for the treatment of this highly debilitating and lethal disease. This approach is not constrained by causative DMD mutations and

  19. Communication between corneal epithelial cells and trigeminal neurons is facilitated by purinergic (P2) and glutamatergic receptors.

    Science.gov (United States)

    Oswald, Duane J; Lee, Albert; Trinidad, Monique; Chi, Cheryl; Ren, Ruiyi; Rich, Celeste B; Trinkaus-Randall, Vickery

    2012-01-01

    Previously, we demonstrated that nucleotides released upon mechanical injury to corneal epithelium activate purinergic (P2) receptors resulting in mobilization of a Ca(2+) wave. However, the tissue is extensively innervated and communication between epithelium and neurons is critical and not well understood. Therefore, we developed a co-culture of primary trigeminal neurons and human corneal limbal epithelial cells. We demonstrated that trigeminal neurons expressed a repertoire of P2Yand P2X receptor transcripts and responded to P2 agonists in a concentration-dependent manner. Mechanical injuries to epithelia in the co-cultures elicited a Ca(2+) wave that mobilized to neurons and was attenuated by Apyrase, an ectonucleotidase. To elucidate the role of factors released from each cell type, epithelial and neuronal cells were cultured, injured, and the wound media from one cell type was collected and added to the other cell type. Epithelial wound media generated a rapid Ca(2+) mobilization in neuronal cells that was abrogated in the presence of Apyrase, while neuronal wound media elicited a complex response in epithelial cells. The rapid Ca(2+) mobilization was detected, which was abrogated with Apyrase, but it was followed by Ca(2+) waves that occurred in cell clusters. When neuronal wound media was preincubated with a cocktail of N-methyl-D-aspartate (NMDA) receptor inhibitors, the secondary response in epithelia was diminished. Glutamate was detected in the neuronal wound media and epithelial expression of NMDA receptor subunit transcripts was demonstrated. Our results indicate that corneal epithelia and neurons communicate via purinergic and NMDA receptors that mediate the wound response in a highly orchestrated manner.

  20. Communication between corneal epithelial cells and trigeminal neurons is facilitated by purinergic (P2 and glutamatergic receptors.

    Directory of Open Access Journals (Sweden)

    Duane J Oswald

    Full Text Available Previously, we demonstrated that nucleotides released upon mechanical injury to corneal epithelium activate purinergic (P2 receptors resulting in mobilization of a Ca(2+ wave. However, the tissue is extensively innervated and communication between epithelium and neurons is critical and not well understood. Therefore, we developed a co-culture of primary trigeminal neurons and human corneal limbal epithelial cells. We demonstrated that trigeminal neurons expressed a repertoire of P2Yand P2X receptor transcripts and responded to P2 agonists in a concentration-dependent manner. Mechanical injuries to epithelia in the co-cultures elicited a Ca(2+ wave that mobilized to neurons and was attenuated by Apyrase, an ectonucleotidase. To elucidate the role of factors released from each cell type, epithelial and neuronal cells were cultured, injured, and the wound media from one cell type was collected and added to the other cell type. Epithelial wound media generated a rapid Ca(2+ mobilization in neuronal cells that was abrogated in the presence of Apyrase, while neuronal wound media elicited a complex response in epithelial cells. The rapid Ca(2+ mobilization was detected, which was abrogated with Apyrase, but it was followed by Ca(2+ waves that occurred in cell clusters. When neuronal wound media was preincubated with a cocktail of N-methyl-D-aspartate (NMDA receptor inhibitors, the secondary response in epithelia was diminished. Glutamate was detected in the neuronal wound media and epithelial expression of NMDA receptor subunit transcripts was demonstrated. Our results indicate that corneal epithelia and neurons communicate via purinergic and NMDA receptors that mediate the wound response in a highly orchestrated manner.

  1. Ibuprofen and Diclofenac Restrict Migration and Proliferation of Human Glioma Cells by Distinct Molecular Mechanisms

    Science.gov (United States)

    Leidgens, Verena; Seliger, Corinna; Jachnik, Birgit; Welz, Tobias; Leukel, Petra; Vollmann-Zwerenz, Arabel; Bogdahn, Ulrich; Kreutz, Marina; Grauer, Oliver M.; Hau, Peter

    2015-01-01

    Background Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with anti-tumorigenic effects in different tumor entities. For glioma, research has generally focused on diclofenac; however data on other NSAIDs, such as ibuprofen, is limited. Therefore, we performed a comprehensive investigation of the cellular, molecular, and metabolic effects of ibuprofen and diclofenac on human glioblastoma cells. Methods Glioma cell lines were treated with ibuprofen or diclofenac to investigate functional effects on proliferation and cell motility. Cell cycle, extracellular lactate levels, lactate dehydrogenase-A (LDH-A) expression and activity, as well as inhibition of the Signal Transducer and Activator of Transcription 3 (STAT-3) signaling pathway, were determined. Specific effects of diclofenac and ibuprofen on STAT-3 were investigated by comparing their effects with those of the specific STAT-3 inhibitor STATTIC. Results Ibuprofen treatment led to a stronger inhibition of cell growth and migration than treatment with diclofenac. Proliferation was affected by cell cycle arrest at different checkpoints by both agents. In addition, diclofenac, but not ibuprofen, decreased lactate levels in all concentrations used. Both decreased STAT-3 phosphorylation; however, diclofenac led to decreased c-myc expression and subsequent reduction in LDH-A activity, whereas treatment with ibuprofen in higher doses induced c-myc expression and less LDH-A alteration. Conclusions This study indicates that both ibuprofen and diclofenac strongly inhibit glioma cells, but the subsequent metabolic responses of both agents are distinct. We postulate that ibuprofen may inhibit tumor cells also by COX- and lactate-independent mechanisms after long-term treatment in physiological dosages, whereas diclofenac mainly acts by inhibition of STAT-3 signaling and downstream modulation of glycolysis. PMID:26485029

  2. Impact of ticagrelor on P2Y1 and P2Y12 localization and on cholesterol levels in platelet plasma membrane.

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    Rabani, Vahideh; Montange, Damien; Meneveau, Nicolas; Davani, Siamak

    2017-10-11

    Ticagrelor is an antiplatelet agent that inhibits platelet activation via P2Y12 antagonism. There are several studies showing that P2Y12 needs lipid rafts to be activated, but there are few data about how ticagrelor impacts lipid raft organization. Therefore, we aimed to investigate how ticagrelor could impact the distribution of cholesterol and consequently alter the organization of lipid rafts on platelet plasma membranes. We identified cholesterol-enriched raft fractions in platelet membranes by quantification of their cholesterol levels. Modifications in cholesterol and protein profiles (Flotillin 1, Flotillin 2, CD36, P2Y1, and P2Y12) were studied in platelets stimulated by ADP, treated by ticagrelor, or both. In ADP-stimulated and ticagrelor-treated groups, we found a decreased level of cholesterol in raft fractions of platelet plasma membrane compared to the control group. In addition, the peak of cholesterol in different experimental groups changed its localization on membrane fractions. In the control group, it was situated on fraction 2, while in ADP-stimulated platelets, it was located in fractions 3 to 5, and in fraction 4 in ticagrelor-treated group. The proteins studied also showed changes in their level of expression and localization in fractions of plasma membrane. Cholesterol levels of plasma membranes have a direct role in the organization of platelet membranes and could be modified by stimulation or drug treatment. Since ticagrelor and ADP both changed lipid composition and protein profile, investigating the lipid and protein composition of platelet membranes is of considerable importance as a focus for further research in anti-platelet management.

  3. KOLONISASI Mus musculus albino DI LABORATORIUM LOKA LITBANG P2B2 BANJARNEGARA

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    Dewi Marbawati

    2012-11-01

    Full Text Available The improvement and development of science and technologycal in health area must be followed with improvement of requirement of test animal would especially white mouse (Mus musculus albino/mencit. Usage of white mouse (mencit because of relatively easy in handling, the size relatively small, the price relatively cheap, once birth can reach 16- 18, have similiarity in circulation system of human and doesn't have ability to vomit because having spillway in bouncing up, that is why white mouse used for drug trial research. This research expected to obtain stable white mouse colony in laboratory to fulfill requirement of white mouse as subject for research.Research was started in March-November 2008 in Loka Litbang P2B2 Banjarnegara. This research was elementary research with observational design. Data were collected from white mouse growth observation. Result of observation showed reproduction of white mouse after 5 month, from 6 white mouse increased become 17 (increased 2 times more, with number of deaths 11,76%. This white mouse survive until 12 months, but the average was 6 month. Oldest mencit until research ends (November 2008 ranges from 8 months. Daily observation data showed that white mouse can bear children until 6/pregnance. According to literature study mouse can bear children average 68/pregnance. Generaly baby mouse was around 1 gram, heavily horns depend on type (strain of white mouse. Result of white mouse weight showed increase of white mouse's body weight every 2 weeks was 8,6 grams. Observation data of development white mouse showed after 4 days the white mouse hair was seen, specially moustache that was clearly seen, on 5 day whole body was white. At the age of 10 days ear opened, part of other body like external mamilla and genitals become explains looked to be. At the age of 12 days eye started opens and active walking.

  4. Excessive Cellular Proliferation Negatively Impacts Reprogramming Efficiency of Human Fibroblasts.

    Science.gov (United States)

    Gupta, Manoj K; Teo, Adrian Kee Keong; Rao, Tata Nageswara; Bhatt, Shweta; Kleinridders, Andre; Shirakawa, Jun; Takatani, Tomozumi; Hu, Jiang; De Jesus, Dario F; Windmueller, Rebecca; Wagers, Amy J; Kulkarni, Rohit N

    2015-10-01

    The impact of somatic cell proliferation rate on induction of pluripotent stem cells remains controversial. Herein, we report that rapid proliferation of human somatic fibroblasts is detrimental to reprogramming efficiency when reprogrammed using a lentiviral vector expressing OCT4, SOX2, KLF4, and cMYC in insulin-rich defined medium. Human fibroblasts grown in this medium showed higher proliferation, enhanced expression of insulin signaling and cell cycle genes, and a switch from glycolytic to oxidative phosphorylation metabolism, but they displayed poor reprogramming efficiency compared with cells grown in normal medium. Thus, in contrast to previous studies, our work reveals an inverse correlation between the proliferation rate of somatic cells and reprogramming efficiency, and also suggests that upregulation of proteins in the growth factor signaling pathway limits the ability to induce pluripotency in human somatic fibroblasts. The efficiency with which human cells can be reprogrammed is of interest to stem cell biology. In this study, human fibroblasts cultured in media containing different concentrations of growth factors such as insulin and insulin-like growth factor-1 exhibited variable abilities to proliferate, with consequences on pluripotency. This occurred in part because of changes in the expression of proteins involved in the growth factor signaling pathway, glycolysis, and oxidative phosphorylation. These findings have implications for efficient reprogramming of human cells. ©AlphaMed Press.

  5. A Local Scalable Distributed EM Algorithm for Large P2P Networks

    Data.gov (United States)

    National Aeronautics and Space Administration — his paper describes a local and distributed expectation maximization algorithm for learning parameters of Gaussian mixture models (GMM) in large peer-to-peer (P2P)...

  6. The ILC P2 Marx and Application of the Marx Topology to Future Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, M.A.; Benwell, A.; Burkhart, C.; Hugyik, J.; Larsen, R.; Macken, K.; MacNair, D.; Nguyen, M.; Olsen, J.; /SLAC

    2011-08-19

    The SLAC P2 Marx is under development as the linac klystron modulator for the ILC. This modulator builds upon the success of the P1 Marx, which is currently undergoing lifetime evaluation. While the SLAC P2 Marx's (henceforth, 'P2 Marx') target application is the ILC, characteristics of the Marx topology make it equally well-suited for operation at different parameter ranges; for example, increased pulse repetition frequency, increased output current, longer pulse width, etc. Marx parameters such as the number of cells, cell capacitance, and component selection can be optimized for the application. This paper provides an overview of the P2 Marx development. In addition, the scalability of the Marx topology to other long-pulse parameter ranges is discussed.

  7. P2P-Based Data System for the EAST Experiment

    Science.gov (United States)

    Shu, Yantai; Zhang, Liang; Zhao, Weifeng; Chen, Haiming; Luo, Jiarong

    2006-06-01

    A peer-to-peer (P2P)-based EAST Data System is being designed to provide data acquisition and analysis support for the EAST superconducting tokamak. Instead of transferring data to the servers, all collected data are stored in the data acquisition subsystems locally and the PC clients can access the raw data directly using the P2P architecture. Both online and offline systems are based on Napster-like P2P architecture. This allows the peer (PC) to act both as a client and as a server. A simulation-based method and a steady-state operational analysis technique are used for performance evaluation. These analyses show that the P2P technique can significantly reduce the completion time of raw data display and real-time processing on the online system, and raise the workload capacity and reduce the delay on the offline system.

  8. Role of P2X7 on steroid synthesis in murine luteal cells

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    Chunping Zhang

    2016-03-01

    Full Text Available The extracellular adenosine triphosphate (ATP regulates different cellular functions through activating purinergic receptors as a signalling molecule or neurotransmitter. P2X7 is highly expressed in murine small luteal cells. In this study, murine luteal cells were cultured in vitro and treated with P2X7 agonists – ATP and 2′(3′-O-(4-benzoyl-benzoyl-adenosine 50-triphosphate (BzATP and with P2X7 antagonist – brilliant blue G (BBG. We found that ATP and BzATP increased the production of progesterone and had no influence on the production of estradiol. BBG reversed the effect of BzATP and ATP. Further studies demonstrated that ATP and BzATP promoted the expression of CYP11A. These results revealed that P2X7 receptor activation is involved in the steroid synthesis in corpus luteum.

  9. Expression, tissue localization and serodiagnostic potential of Taenia multiceps acidic ribosomal protein P2.

    Science.gov (United States)

    Huang, Xing; Chen, Lin; Yang, Yingdong; Gu, Xiaobin; Wang, Yu; Lai, Weimin; Peng, Xuerong; Yang, Guangyou

    2015-12-01

    The larval stage of Taenia multiceps, also known as coenurus, is the causative agent of coenurosis, which results in severe health problems in sheep, goats, cattle and other animals that negatively impact on animal husbandry. There is no reliable method to identify coenurus infected goats in the early period of infection. We identified a full-length cDNA that encodes acidic ribosomal protein P2 from the transcriptome of T. multiceps (TmP2). Following cloning, sequencing and structural analyses were performed using bioinformatics tools. Recombinant TmP2 (rTmP2) was prokaryotically expressed and then used to test immunoreactivity and immunogenicity in immunoblotting assays. The native proteins in adult stage and coenurus were located via immunofluorescence assays, while the potential of rTmP2 for indirect ELISA-based serodiagnostics was assessed using native goat sera. In addition, 20 goats were randomly divided into a drug treatment group and a control group. Each goat was orally given mature, viable T. multiceps eggs. The drug treatment group was given 10% praziquantel by intramuscular injection 45 days post-infection (p.i), and all goats were screened for anti-TmP2 antibodies with the indirect ELISA method established here, once a week for 17 weeks p.i. The open reading frame (366 bp) of the target gene encodes a 12.62 kDa protein, which showed high homology to that from Taenia solium (93% identity) and lacked a signal peptide. Immunofluorescence staining showed that TmP2 was highly localized to the parenchymatous zone of both the adult parasite and the coenurus; besides, it was widely distributed in cystic wall of coenurus. Building on good immunogenic properties, rTmP2-based ELISA exhibited a sensitivity of 95.0% (19/20) and a specificity of 96.3% (26/27) in detecting anti-P2 antibodies in the sera of naturally infected goats and sheep. In goats experimentally infected with T. multiceps, anti-TmP2 antibody was detectable in the control group from 3 to 10 weeks

  10. Corneal epithelium expresses a variant of P2X(7 receptor in health and disease.

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    Courtney Mankus

    Full Text Available Improper wound repair of the corneal epithelium can alter refraction of light resulting in impaired vision. We have shown that ATP is released after injury, activates purinergic receptor signaling pathways and plays a major role in wound closure. In many cells or tissues, ATP activates P2X(7 receptors leading to cation fluxes and cytotoxicity. The corneal epithelium is an excellent model to study the expression of both the full-length P2X(7 form (defined as the canonical receptor and its truncated forms. When Ca(2+ mobilization is induced by BzATP, a P2X(7 agonist, it is attenuated in the presence of extracellular Mg(2+ or Zn(2+, negligible in the absence of extracellular Ca(2+, and inhibited by the competitive P2X7 receptor inhibitor, A438079. BzATP enhanced phosphorylation of ERK. Together these responses indicate the presence of a canonical or full-length P2X(7 receptor. In addition BzATP enhanced epithelial cell migration, and transfection with siRNA to the P2X(7 receptor reduced cell migration. Furthermore, sustained activation did not induce dye uptake indicating the presence of truncated or variant forms that lack the ability to form large pores. Reverse transcription-polymerase chain reaction and Northern blot analysis revealed a P2X(7 splice variant. Western blots identified a full-length and truncated form, and the expression pattern changed as cultures progressed from monolayer to stratified. Cross-linking gels demonstrated the presence of homo- and heterotrimers. We examined epithelium from age matched diabetic and non-diabetic corneas patients and detected a 4-fold increase in P2X(7 mRNA from diabetic corneal epithelium compared to non-diabetic controls and an increased trend in expression of P2X(7variant mRNA. Taken together, these data indicate that corneal epithelial cells express full-length and truncated forms of P2X(7, which ultimately allows P2X(7 to function as a multifaceted receptor that can mediate cell proliferation and

  11. DESENSITIZATION PROPERTIES OF P2X3 RECEPTORS SHAPING PAIN SIGNALLING

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    Rashid eGiniatullin

    2013-12-01

    Full Text Available ATP-gated P2X3 receptors are mostly expressed by nociceptive sensory neurons and participate in transduction of pain signals. P2X3 receptors show a combination of fast desensitization onset and slo