c-myc overexpression causes anaplasia in medulloblastoma.

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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.

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

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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.

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

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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.

Four regulatory elements in the human c-fos promoter mediate transactivation by HTLV-1 Tax protein.

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Alexandre, C; Verrier, B

1991-04-01

Expression of the human c-fos proto-oncogene is activated in trans by the Tax protein encoded by human T-cell leukemia virus type-1 (HTLV-1). Indeed, we show here that a HeLa clone stably transfected by Tax expresses Fos at a high level. We also show that multiple elements of the human c-fos promoter, i.e. the v-sis conditioned medium inducible element (SIE), the dyad symmetry element (DSE) necessary for growth factor induction, the octanucleotide direct repeat element (DR), and the cyclic AMP response element (CRE) centred at -60, can all mediate Tax transactivation. In the DSE, the 10bp central core that binds the serum response factor (SRF) is, by itself, sufficient to mediate Tax transactivation. Moreover, a CRE-binding protein is involved in Tax activation through the CRE-60 element. Since Fos is a transregulator of cellular genes, our results suggest that the oncoprotein plays a crucial role in T-cell transformation by HTLV-1 in conjunction with other Tax-inducible genes.

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

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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.

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.

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

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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.

Expression of proto-oncogenes in non-Hodgkin's lymphomas by in situ hybridization with biotinylated DNA probes

International Nuclear Information System (INIS)

Hamatani, Kiyohiro; Yoshida, Kuniko; Abe, Masumi; Shimaoka, Katsutaro; Shiku, Hiroshi; Akiyama, Mitoshi; Kondo, Hisayoshi.

1989-11-01

Expression of six proto-oncogenes (fos, myc, myb, Ki-ras, Ha-ras, and N-ras) in 43 cases of non-Hodgkin's lymphoma was analyzed by means of in situ hybridization. Biotinylated DNA probes of the six oncogenes and those of the immunoglobulin H-chain (IgH) gene and the T cell receptor β-chain (TCRβ) gene were used. The results of in situ hybridization performed under blind conditions by IgH and TCRβ gene probes were compatible with those of typing by cell surface markers. The nuclear protein-related proto-oncogenes, fos myc, and myb, were expressed in about 70 % - 80 % of all cases regardless of phenotypes, histology or histologic grade. On the contrary, genes of the ras family were expressed in fewer cases except for the Ki-ras gene which was more frequently expressed by cases of the T cell immunophenotype with a high malignancy grade. The results of dot hybridization with RNA extracted from some cases were compatible with those of in situ hybridization, further demonstrating the specificity of in situ hybridization. (author)

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

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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

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

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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

Dynamic acetylation of all lysine 4-methylated histone H3 in the mouse nucleus: analysis at c-fos and c-jun.

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Catherine A Hazzalin

2005-12-01

Full Text Available A major focus of current research into gene induction relates to chromatin and nucleosomal regulation, especially the significance of multiple histone modifications such as phosphorylation, acetylation, and methylation during this process. We have discovered a novel physiological characteristic of all lysine 4 (K4-methylated histone H3 in the mouse nucleus, distinguishing it from lysine 9-methylated H3. K4-methylated histone H3 is subject to continuous dynamic turnover of acetylation, whereas lysine 9-methylated H3 is not. We have previously reported dynamic histone H3 phosphorylation and acetylation as a key characteristic of the inducible proto-oncogenes c-fos and c-jun. We show here that dynamically acetylated histone H3 at these genes is also K4-methylated. Although all three modifications are proven to co-exist on the same nucleosome at these genes, phosphorylation and acetylation appear transiently during gene induction, whereas K4 methylation remains detectable throughout this process. Finally, we address the functional significance of the turnover of histone acetylation on the process of gene induction. We find that inhibition of turnover, despite causing enhanced histone acetylation at these genes, produces immediate inhibition of gene induction. These data show that all K4-methylated histone H3 is subject to the continuous action of HATs and HDACs, and indicates that at c-fos and c-jun, contrary to the predominant model, turnover and not stably enhanced acetylation is relevant for efficient gene induction.

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...

Ultraviolet B (UVB) induction of the c-fos promoter is mediated by phospho-cAMP response element binding protein (CREB) binding to CRE and c-fos activator protein 1 site (FAP1) cis elements.

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Gonzales, Melissa; Bowden, G Tim

2002-06-26

The ultraviolet B (UVB) portion (280-320 nm) of the ultraviolet spectrum has been shown to contribute to the development of non-melanoma skin cancer in humans. Research in the human keratinocyte cell line, HaCaT, revealed that UVB irradiation caused the upregulation of the transcription factor activator protein-1 (AP-1). The AP-1 complex formed in UVB-irradiated HaCaT cells is specifically composed of c-fos and Jun D. c-Fos expression was induced in a manner that correlated with the UVB-induced activation of AP-1. To investigate how c-fos expression is regulated by UVB irradiation, the role of each of four cis elements within the c-fos promoter was evaluated. Clustered point mutations at the sis inducible element (SIE), serum response element (SRE), c-fos AP-1 site (FAP1), or cyclic AMP response elements (CRE) significantly inhibited UVB induction of the c-fos promoter. This indicated that all four cis elements are required for maximum promoter activity. The CRE and FAP1 elements were the two most active cis elements that mediate the UVB transactivation of c-fos. Homodimers of phosphorylated cAMP response element binding protein (CREB) were induced by UVB irradiation to bind to each of these elements. Therefore, CREB may function as an important regulatory protein in the UVB-induced expression of c-fos.

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...

Essential role of RSK2 in c-Fos-dependent osteosarcoma development.

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David, Jean-Pierre; Mehic, Denis; Bakiri, Latifa; Schilling, Arndt F; Mandic, Vice; Priemel, Matthias; Idarraga, Maria Helena; Reschke, Markus O; Hoffmann, Oskar; Amling, Michael; Wagner, Erwin F

2005-03-01

Inactivation of the growth factor-regulated S6 kinase RSK2 causes Coffin-Lowry syndrome in humans, an X-linked mental retardation condition associated with progressive skeletal abnormalities. Here we show that mice lacking RSK2 develop a progressive skeletal disease, osteopenia due to impaired osteoblast function and normal osteoclast differentiation. The phenotype is associated with decreased expression of Phex, an endopeptidase regulating bone mineralization. This defect is probably not mediated by RSK2-dependent phosphorylation of c-Fos on serine 362 in the C-terminus. However, in the absence of RSK2, c-Fos-dependent osteosarcoma formation is impaired. The lack of c-Fos phosphorylation leads to reduced c-Fos protein levels, which are thought to be responsible for decreased proliferation and increased apoptosis of transformed osteoblasts. Therefore, RSK2-dependent stabilization of c-Fos is essential for osteosarcoma formation in mice and may also be important for human osteosarcomas.

c-Fos expression during temporal order judgment in mice.

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Makoto Wada

Full Text Available The neuronal mechanisms for ordering sensory signals in time still need to be clarified despite a long history of research. To address this issue, we recently developed a behavioral task of temporal order judgment in mice. In the present study, we examined the expression of c-Fos, a marker of neural activation, in mice just after they carried out the temporal order judgment task. The expression of c-Fos was examined in C57BL/6N mice (male, n = 5 that were trained to judge the order of two air-puff stimuli delivered bilaterally to the right and left whiskers with stimulation intervals of 50-750 ms. The mice were rewarded with a food pellet when they responded by orienting their head toward the first stimulus (n = 2 or toward the second stimulus (n = 3 after a visual "go" signal. c-Fos-stained cell densities of these mice (test group were compared with those of two control groups in coronal brain sections prepared at bregma -2, -1, 0, +1, and +2 mm by applying statistical parametric mapping to the c-Fos immuno-stained sections. The expression of c-Fos was significantly higher in the test group than in the other groups in the bilateral barrel fields of the primary somatosensory cortex, the left secondary somatosensory cortex, the dorsal part of the right secondary auditory cortex. Laminar analyses in the primary somatosensory cortex revealed that c-Fos expression in the test group was most evident in layers II and III, where callosal fibers project. The results suggest that temporal order judgment involves processing bilateral somatosensory signals through the supragranular layers of the primary sensory cortex and in the multimodal sensory areas, including marginal zone between the primary somatosensory cortex and the secondary sensory cortex.

Polymerase chain reaction-based detection of myc transduction in feline leukemia virus-infected cats.

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Sumi, Ryosuke; Miyake, Ariko; Endo, Taiji; Ohsato, Yoshiharu; Ngo, Minh Ha; Nishigaki, Kazuo

2018-04-01

Feline lymphomas are associated with the transduction and activation of cellular proto-oncogenes, such as c-myc, by feline leukemia virus (FeLV). We describe a polymerase chain reaction assay for detection of myc transduction usable in clinical diagnosis. The assay targets c-myc exons 2 and 3, which together result in a FeLV-specific fusion gene following c-myc transduction. When this assay was conducted on FeLV-infected feline tissues submitted for clinical diagnosis of tumors, myc transduction was detected in 14% of T-cell lymphoma/leukemias. This newly established system could become a useful diagnostic tool in veterinary medicine.

Adsorption kinetics of c-Fos and c-Jun to air-water interfaces.

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Del Boca, Maximiliano; Nobre, Thatyane Morimoto; Zaniquelli, Maria Elisabete Darbello; Maggio, Bruno; Borioli, Graciela A

2007-11-01

The kinetics of adsorption to air-water interfaces of the biomembrane active transcription factors c-Fos, c-Jun and their mixtures is investigated. The adsorption process shows three distinct stages: a lag time, a fast pseudo zero-order stage, and a halting stage. The initial stage determines the course of the process, which is concentration dependent until the end of the fast stage. We show that c-Fos has faster adsorption kinetics than c-Jun over all three stages and that the interaction between both proteins is apparent in the adsorption profiles of the mixtures. Protein molecular reorganization at the interface determines the transition to the final adsorption stage of the pure proteins as well as that of the mixtures.

Effects of 12-O-tetradecanoyl-phorbol-13-acetate [corrected] and sodium lauryl sulfate on the production and expression of cytokines and proto-oncogenes in photoaged and intrinsically aged human keratinocytes.

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Suh, D H; Youn, J I; Eun, H C

2001-11-01

Skin aging may be divided into photoaging and intrinsic aging. The purpose of this study was to investigate the effects of 12-O-tetradecanoyl-phorbol-13-acetate and sodium lauryl sulfate on the production and expression of cytokines and proto-oncogenes in photoaged and intrinsically aged skin, compared with young skin. Keratinocytes were taken from newborns, young adults in their twenties, and from the forearm and thigh of volunteers in their fifties and seventies. Interleukin-1alpha and -6, and interleukin-1 receptor antagonist, c-fos and c-myc were measured after cultured keratinocytes had been treated with 12-O-tetradecanoyl-phorbol-13-acetate and sodium lauryl sulfate. There has been no report concerning the dependence of cytokine production by sodium lauryl sulfate upon photoaging and intrinsic aging. This study also involves the first investigation of the effects of aging on c-myc expression by 12-O-tetradecanoyl-phorbol-13-acetate treatment. Cytokine production decreased markedly with age. These results suggest the progressive decline of cellular function with age. The ratio of cytokine production in the irritant-treated group compared with that in the control group showed a different pattern in photoaging and intrinsic aging. With the significant difference between photoaging and intrinsic aging, T/C ratio decreased in interleukin-1alpha and interleukin-1 receptor antagonist upon aging, whereas it increased in interleukin-6. S/C ratio was uniquely elevated on photoaged skin in the 50 y age group. It is suggested that photoaged skin shows an exaggerated reaction to surfactant. Compared with the control, c-fos expression in 12-O-tetradecanoyl-phorbol-13-acetate-treated keratinocytes decreased with age in the thigh, but increased in the photoaged skin of forearm. The increased c-fos expression in 12-O-tetradecanoyl-phorbol-13-acetate-treated keratinocytes could be relevant for the predisposition of photoaged keratinocytes to malignant transformation.

Retrovirus-mediated gene transfer of a human c-fos cDNA into mouse bone marrow stromal cells.

Science.gov (United States)

Roux, P; Verrier, B; Klein, B; Niccolino, M; Marty, L; Alexandre, C; Piechaczyk, M

1991-11-01

A cDNA encoding a complete human c-fos protein was isolated and inserted into two different murine MoMuLV-derived recombinant retroviruses allowing expression of c-fos protein in different cell types. One c-fos-expressing retrovirus, chosen for its ability to express high levels of proteins in fibroblast-like cells, was shown to potentiate long-term cultures of mouse bone marrow stromal cells in vitro and therefore constitutes a potential tool for immortalizing such cells. Moreover, when tested in an in vitro differentiation assay, stromal cells constitutively expressing c-fos favor the granulocyte differentiation of hematopoietic precursors. Interestingly, retroviruses expressing v-src and v-abl oncogenes, included as controls in our experiments, do not produce any detectable effects, whereas those expressing polyoma virus middle T antigen facilitate long-term growth in vitro of stromal cells that favor the macrophage differentiation pathway of bone marrow stem cells. Our observation supports the idea that constitutive expression of some oncogenes, including c-fos and polyoma virus middle T antigen, may influence cytokine production by bone marrow stromal cells.

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

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.

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.

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

Energy Technology Data Exchange (ETDEWEB)

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.

On the functional significance of c-fos induction during the sleep-waking cycle.

Science.gov (United States)

Cirelli, C; Tononi, G

2000-06-15

A striking finding in recent years has been that the transition from sleep to waking is accompanied in many brain regions by a widespread activation of c-fos and other immediate-early genes (IEGs). IEGs are induced by various electrical or chemical signals to which neural cells are exposed and their protein products act as transcription factors to regulate the expression of other genes. After a few hours of sleep, the expression of these transcription factors in the brain is absent or restricted to very few cells. However, after a few hours of spontaneous waking or sleep deprivation, the expression of c-fos and other IEGs is high in cerebral cortex, hypothalamus, septum, and several thalamic and brainstem nuclei. While cells expressing c-fos during waking are widely distributed, they represent only a subset of all neurons in any given area. These observations raise several questions: Why is c-fos expressed during waking and not during sleep? Is waking always accompanied by c-fos induction? Which subset of cells express c-fos during waking and why only a subset? Once c-fos has been induced, what are the functional consequences of its activation? In this review, we summarize our current understanding of the meaning of c-fos activation in the brain in relation to the sleep-waking cycle and suggest that c-fos induction in the cerebral cortex during waking might be related to the occurrence of plastic phenomena.

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.

Characterization of the promoter region of the human c-erbB-2 protooncogene

International Nuclear Information System (INIS)

Ishii, S.; Imamoto, F.; Yamanashi, Y.; Toyoshima, K.; Yamamoto, T.

1987-01-01

Three overlapping genomic clones that contain the 5'-terminal portion of the human c-erbB-2 gene (ERBB2) were isolated. The promoter region was identified by nuclease S1 mapping with c-erbB-2 mRNA. Seven transcriptional start sites were identified. DNA sequence analysis showed that the promoter region contains a TATA box and a CAAT box about 30 and 80 base pairs (bp), respectively, upstream of the most downstream RNA initiation site. Two putative binding sites for transcription factor Sp1 were identified about 50 and 110 bp upstream of the CAAT box, and six GGA repeats were found between the CAAT box and the TATA box. This region had strong promoter activity when placed upstream of the bacterial chloramphenicol acetyltransferase gene and transfected into monkey CV-1 cells. These data indicate that the promoter of the human c-erbB-2 protooncogene is different from that of the protooncogene c-erbB-1 (epidermal growth factor receptor gene), which does not contain either a TATA box or a CAAT box. Comparison of the promoter sequences and activities of the two protooncogenes should be helpful in analysis of the regulatory mechanism of expression of their gene products, which are growth-factor receptors

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.

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.

Expression of myc family oncoproteins in small-cell lung-cancer cell lines and xenografts

DEFF Research Database (Denmark)

Rygaard, K; Vindeløv, L L; Spang-Thomsen, M

1993-01-01

A number of genes have altered activity in small-cell lung cancer (SCLC), but especially genes of the myc family (c-myc, L-myc and N-myc) are expressed at high levels in SCLC. Most studies have explored expression at the mRNA level, whereas studies of myc family oncoprotein expression are sparse....... WE examined the expression of myc proto-oncogenes at the mRNA and protein level in 23 cell lines or xenografts. In the cell lines, the doubling time and the cell-cycle distribution, as determined by flow-cytometric DNA analysis, were examined to establish whether the level of myc......-myc. In general, the level of expression of c-myc and N-myc was similar at the mRNA and the protein level. Expression of c-myc was positively correlated with the proliferative index (sum of S and G2+M phases) of cell lines, but not with the population doubling time. In general, L-myc-expressing cell lines had...

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

Directory of Open Access Journals (Sweden)

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.

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

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

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.

Differential induction of c-Fos and phosphorylated ERK by a noxious stimulus after peripheral nerve injury.

Science.gov (United States)

Tabata, Mitsuyasu; Terayama, Ryuji; Maruhama, Kotaro; Iida, Seiji; Sugimoto, Tomosada

2018-03-01

In this study, we compared induction of c-Fos and phosphorylated extracellular signal-regulated kinase (p-ERK) in the spinal dorsal horn after peripheral nerve injury. We examined the spinal dorsal horn for noxious heat-induced c-Fos and p-ERK protein-like immunoreactive (c-Fos- and p-ERK-IR) neuron profiles after tibial nerve injury. The effect of administration of a MEK 1/2 inhibitor (PD98059) on noxious heat-induced c-Fos expression was also examined after tibial nerve injury. A large number of c-Fos- and p-ERK-IR neuron profiles were induced by noxious heat stimulation to the hindpaw in sham-operated animals. A marked reduction in the number of c-Fos- and p-ERK-IR neuron profiles was observed in the medial 1/3 (tibial territory) of the dorsal horn at 3 and 7 days after nerve injury. Although c-Fos-IR neuron profiles had reappeared by 14 days after injury, the number of p-ERK-IR neuron profiles remained decreased in the tibial territory of the superficial dorsal horn. Double immunofluorescence labeling for c-Fos and p-ERK induced by noxious heat stimulation to the hindpaw at different time points revealed that a large number of c-Fos-IR, but not p-ERK-IR, neuron profiles were distributed in the tibial territory after injury. Although administration of a MEK 1/2 inhibitor to the spinal cord suppressed noxious heat-induced c-Fos expression in the peroneal territory, this treatment did not alter c-Fos induction in the tibial territory after nerve injury. ERK phosphorylation may be involved in c-Fos induction in normal nociceptive responses, but not in exaggerated c-Fos induction after nerve injury.

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.

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.

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.

Absence of PDGF-induced, PKC-independent c-fos expression in a chemically transformed C3H/10T1/2 cell clone.

Science.gov (United States)

Vassbotn, F S; Skar, R; Holmsen, H; Lillehaug, J R

1992-09-01

The effect of platelet-derived growth factor (PDGF) on c-fos mRNA transcription was studied in the immortalized mouse embryo fibroblast C3H/10T1/2 Cl 8 (10T1/2) cells and the chemically transformed, tumorigenic subclone C3H/10T1/2 Cl 16 (Cl 16). In the 10T1/2 cells as well as the Cl 16 subclone, the dose-dependent PDGF stimulation of c-fos mRNA synthesis was similar in both logarithmically growing and confluent cultures. c-fos mRNA was induced severalfold by 12-O-tetradecanoylphorbol-13-acetate (TPA) in both 10T1/2 and Cl 16. Down-regulation of protein kinase C (PKC) activity by TPA pretreatment inhibited PDGF-stimulated c-fos mRNA expression in Cl 16 cells but did not affect this induction in the 10T1/2 cells. This inhibition was not a general phenomenon of 3-methylcholanthrene-mediated transformation of 10T1/2 cells since experiments with another transformed 10T1/2 cell clone, C3H/10T1/2 TPA 482, gave qualitatively the same results as the 10T1/2 cells. Receptor binding experiments showed that the nontransformed and transformed cells had a comparable number of PDGF receptors, 1.3 x 10(5) and 0.7 x 10(5) receptors per cell, respectively. Furthermore, cAMP-induced c-fos expression induced by forskolin is formerly shown to be independent of PKC down-regulation. In our experiments, forskolin induced c-fos expression in both clones. However, PKC down-regulation inhibited the forskolin-induced c-fos expression in Cl 16 cells. This apparently demonstrates cross talk between PKC and PKA in the c-fos induction pathway. The present results provide evidence for an impaired mechanism for activating c-fos expression through PKC-independent, PDGF-induced signal transduction in the chemically transformed Cl 16 fibroblasts compared to that in nontransformed 10T1/2 cells.

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

Science.gov (United States)

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.

IP3-dependent intracellular Ca2+ release is required for cAMP-induced c-fos expression in hippocampal neurons

International Nuclear Information System (INIS)

Zhang, Wenting; Tingare, Asmita; Ng, David Chi-Heng; Johnson, Hong W.; Schell, Michael J.; Lord, Rebecca L.; Chawla, Sangeeta

2012-01-01

Highlights: ► cAMP-induced c-fos expression in hippocampal neurons requires a submembraneous Ca 2+ pool. ► The submembraneous Ca 2+ pool derives from intracellular ER stores. ► Expression of IP 3 -metabolizing enzymes inhibits cAMP-induced c-fos expression. ► SRE-mediated and CRE-mediated gene expression is sensitive to IP 3 -metabolizing enzymes. ► Intracellular Ca 2+ release is required for cAMP-induced nuclear translocation of TORC1. -- Abstract: Ca 2+ and cAMP are widely used in concert by neurons to relay signals from the synapse to the nucleus, where synaptic activity modulates gene expression required for synaptic plasticity. Neurons utilize different transcriptional regulators to integrate information encoded in the spatiotemporal dynamics and magnitude of Ca 2+ and cAMP signals, including some that are Ca 2+ -responsive, some that are cAMP-responsive and some that detect coincident Ca 2+ and cAMP signals. Because Ca 2+ and cAMP can influence each other’s amplitude and spatiotemporal characteristics, we investigated how cAMP acts to regulate gene expression when increases in intracellular Ca 2+ are buffered. We show here that cAMP-mobilizing stimuli are unable to induce expression of the immediate early gene c-fos in hippocampal neurons in the presence of the intracellular Ca 2+ buffer BAPTA-AM. Expression of enzymes that attenuate intracellular IP 3 levels also inhibited cAMP-dependent c-fos induction. Synaptic activity induces c-fos transcription through two cis regulatory DNA elements – the CRE and the SRE. We show here that in response to cAMP both CRE-mediated and SRE-mediated induction of a luciferase reporter gene is attenuated by IP 3 metabolizing enzymes. Furthermore, cAMP-induced nuclear translocation of the CREB coactivator TORC1 was inhibited by depletion of intracellular Ca 2+ stores. Our data indicate that Ca 2+ release from IP 3 -sensitive pools is required for cAMP-induced transcription in hippocampal neurons.

c-Fos downregulation positively regulates EphA5 expression in a congenital hypothyroidism rat model.

Science.gov (United States)

Song, Honghua; Zheng, Yuqin; Cai, Fuying; Ma, Yanyan; Yang, Jingyue; Wu, Youjia

2018-04-01

The EphA5 receptor is well established as an axon guidance molecule during neural system development and plays an important role in dendritic spine formation and synaptogenesis. Our previous study has showed that EphA5 is decreased in the developing brain of congenital hypothyroidism (CH) and the EphA5 promoter methylation modification participates in its decrease. c-Fos, a well-kown transcription factor, has been considered in association with brain development. Bioinformatics analysis showed that the EphA5 promoter region contained five putative c-fos binding sites. The chromatin immunoprecipitation (ChIP) assays were used to assess the direct binding of c-fos to the EphA5 promoter. Furthermore, dual-luciferase assays showed that these three c-fos protein binding sites were positive regulatory elements for EphA5 expression in PC12 cells. Moreover, We verified c-fos positively regulation for EphA5 expression in CH model. Q-PCR and Western blot showed that c-fos overexpression could upregulate EphA5 expression in hippocampal neurons of rats with CH. Our results suggest that c-fos positively regulates EphA5 expression in CH rat model.

Acute restraint stress decreases c-fos immunoreactivity in hilar mossy cells of the adult dentate gyrus

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Moretto, Jillian N.; Duffy, Áine M.

2017-01-01

Although a great deal of information is available about the circuitry of the mossy cells (MCs) of the dentate gyrus (DG) hilus, their activity in vivo is not clear. The immediate early gene c-fos can be used to gain insight into the activity of MCs in vivo, because c-fos protein expression reflects increased neuronal activity. In prior work, it was identified that control rats that were perfusion-fixed after removal from their home cage exhibited c-fos immunoreactivity (ir) in the DG in a spatially stereotyped pattern: ventral MCs and dorsal granule cells (GCs) expressed c-fos protein (Duffy et al., Hippocampus 23:649–655, 2013). In this study, we hypothesized that restraint stress would alter c-fos-ir, because MCs express glucocorticoid type 2 receptors and the DG is considered to be involved in behaviors related to stress or anxiety. We show that acute restraint using a transparent nose cone for just 10 min led to reduced c-fos-ir in ventral MCs compared to control rats. In these comparisons, c-fos-ir was evaluated 30 min after the 10 min-long period of restraint, and if evaluation was later than 30 min c-fos-ir was no longer suppressed. Granule cells (GCs) also showed suppressed c-fos-ir after acute restraint, but it was different than MCs, because the suppression persisted for over 30 min after the restraint. We conclude that c-fos protein expression is rapidly and transiently reduced in ventral hilar MCs after a brief period of restraint, and suppressed longer in dorsal GCs. PMID:28190104

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

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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.

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

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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.

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

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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.

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....

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.

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.

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

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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.

A pathological study on overexpression of c-fos and Rb proteins in human radiation skin ulcer

International Nuclear Information System (INIS)

Du Yuejiao; Wang Dewen; Gao Yabing

1996-01-01

We performed an immunohistochemical study on human radiation skin ulcer by using antibodies against c-fos and Rb proteins and antigen-repairing method with a microwave oven. We found that the positive rates of overexpression of c-fos and Rb proteins were 84.0% and 100%, respectively. The overexpression of c-fos protein was mainly observed in cell nuclei of squamous epithelial cells, fibroblasts, endothelial cells, and leiomyocytes in media and fibrocytes in adventitia of arterioles. The location of the Rb protein overexpression was mostly similar to that of c-fos protein. The overexpression of c-fos and Rb proteins may be related to cancer transformation and poor healing of radiation-induced skin ulcers

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

Regulation of expression of the c-sis proto-oncogene

Energy Technology Data Exchange (ETDEWEB)

Ratner, L. (Washington Univ., St. Louis, MO (USA))

1989-06-12

Regulation of expression of platelet derived growth factor polypeptide B encoded by the c-sis proto-oncogene is important in a number of physiological and pathological conditions. Sequences in the 1,028 nucleotide long 5{prime} untranslated region of the c-sis mRNA were found to inhibit protein synthesis. The inhibition is relieved by deletion of nucleotides 154-378 or 398-475. Sequences within 375 nucleotides upstream of the RNA initiation sites are important for transcriptional activity. Sequences in two portions of this region, between {minus}375 and {minus}235 nucleotides and between {minus}235 and {minus}99 nucleotides relative to the RNA CAP site are important for full activity. A transcriptional enhancer activity is demonstrated by its ability to increase the activity of the human T lymphotropic virus type (HTLV) I promoter at a distance and in an orientation-independent manner. Furthermore, sequences upstream of the c-sis RNA CAP site respond to the HTLV I transactivator protein to increase RNA synthesis from either the c-sis or HTLV I promoter.

Spatial memory extinction: a c-Fos protein mapping study.

Science.gov (United States)

Méndez-Couz, M; Conejo, N M; Vallejo, G; Arias, J L

2014-03-01

While the neuronal basis of spatial memory consolidation has been thoroughly studied, the substrates mediating the process of extinction remain largely unknown. This study aimed to evaluate the functional contribution of selected brain regions during the extinction of a previously acquired spatial memory task in the Morris water maze. For that purpose, we used adult male Wistar rats trained in a spatial reference memory task. Learning-related changes in c-Fos inmunoreactive cells after training were evaluated in cortical and subcortical regions. Results show that removal of the hidden platform in the water maze induced extinction of the previously reinforced escape behavior after 16 trials, without spontaneous recovery 24h later. Extinction was related with significantly higher numbers of c-Fos positive nuclei in amygdala nuclei and prefrontal cortex. On the other hand, the lateral mammillary bodies showed higher number of c-Fos positive cells than the control group. Therefore, in contrast with the results obtained in studies of classical conditioning, we show the involvement of diencephalic structures mediating this kind of learning. In summary, our findings suggest that medial prefrontal cortex, the amygdala complex and diencephalic structures like the lateral mammillary nuclei are relevant for the extinction of spatial memory. Copyright © 2013 Elsevier B.V. All rights reserved.

Forced expression of stabilized c-Fos in dendritic cells reduces cytokine production and immune responses in vivo

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Ryoko; Suzuki, Mayu; Sakaguchi, Ryota; Hasegawa, Eiichi; Kimura, Akihiro; Shichita, Takashi; Sekiya, Takashi [Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku-ku, Tokyo 160-8582 (Japan); Japan Science and Technology Agency, CREST, Chiyoda-ku 102-0075 (Japan); Shiraishi, Hiroshi [Division of Medical Biochemistry, Department of Biomolecular Sciences, Saga Medical School, Saga (Japan); Shimoda, Kouji [Department of Laboratory Animal Center, Keio University School of Medicine, Tokyo (Japan); Yoshimura, Akihiko, E-mail: yoshimura@a6.keio.jp [Department of Microbiology and Immunology, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku-ku, Tokyo 160-8582 (Japan); Japan Science and Technology Agency, CREST, Chiyoda-ku 102-0075 (Japan)

2012-06-29

Highlights: Black-Right-Pointing-Pointer Dendritic cells expressing stabilized c-Fos produced less inflammatory cytokines. Black-Right-Pointing-Pointer Dendritic cells expressing stabilized c-Fos activated T cells less efficiently. Black-Right-Pointing-Pointer Transgenic mice expressing stabilized c-Fos were resistant to EAE model. -- Abstract: Intracellular cyclic adenosine monophosphate (cAMP) suppresses innate immunity by inhibiting proinflammatory cytokine production by monocytic cells. We have shown that the transcription factor c-Fos is responsible for cAMP-mediated suppression of inflammatory cytokine production, and that c-Fos protein is stabilized by IKK{beta}-mediated phosphorylation. We found that S308 is one of the major phosphorylation sites, and that the S308D mutation prolongs c-Fos halflife. To investigate the role of stabilized c-Fos protein in dendritic cells (DCs) in vivo, we generated CD11c-promoter-deriven c-FosS308D transgenic mice. As expected, bone marrow-derived DCs (BMDCs) from these Tg mice produced smaller amounts of inflammatory cytokines, including TNF-{alpha}, IL-12, and IL-23, but higher levels of IL-10, in response to LPS, than those from wild-type (Wt) mice. When T cells were co-cultured with BMDCs from Tg mice, production of Th1 and Th17 cytokines was reduced, although T cell proliferation was not affected. Tg mice demonstrated more resistance to experimental autoimmune encephalomyelitis (EAE) than did Wt mice. These data suggest that c-Fos in DCs plays a suppressive role in certain innate and adaptive immune responses.

Mechanism of estrogen activation of c-myc oncogene expression.

Science.gov (United States)

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.

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.

Effects of interleukin-7/interleukin-7 receptor on RANKL-mediated osteoclast differentiation and ovariectomy-induced bone loss by regulating c-Fos/c-Jun pathway.

Science.gov (United States)

Zhao, Ji-Jun; Wu, Zhao-Feng; Yu, Ying-Hao; Wang, Ling; Cheng, Li

2018-09-01

To explore the effects of IL-7/IL-7R on the RANKL-mediated osteoclast differentiation in vitro and OVX-induced bone loss in vivo. BMMs and RAW264.7 were transfected with IL-7, IL-7R siRNA, c-Fos siRNA, and c-jun siRNA and later stimulated by RANKL. TRAP and toluidine blue staining were used to observe osteoclast formation and bone resorption, respectively. HE and TRAP staining were used to detect trabecular bone microstructure and osteoclasts of mice, respectively. qRT-PCR and Western blot analysis were used to examine expression. IL-7 unregulated the expression of CTSK, NFATc1, MMP9, and the phosphorylation of p38 and Akt by activating the c-Fos/c-Jun pathway, which increased osteoclast numbers and bone resorption in RANKL-stimulated macrophages. While IL-7R siRNA and c-Fos siRNA decreased the expression, as well as and the phosphorylation of p38 and Akt.IL-7 decreased the BMD and OPG expression in OVX-induced mice and increased the TRAP positive cells, the mRNA expression of c-fos, c-jun, and RANKL, which was contradictory to IL-7R siRNA, and c-Fos siRNA. Furthermore, IL-7R siRNA and c-Fos siRNA caused thicker trabeculae, increased trabecular number, and decreased osteolysis in OVX mice. IL-7/IL-7R can promote RANKL-mediated osteoclast formation and bone resorption by activating the c-Fos/c-Jun pathway, as well as inducing bone loss in OVX mice. © 2018 Wiley Periodicals, Inc.

Expression of hepatocyte growth factor and the proto-oncogenic receptor c-Met in canine osteosarcoma

NARCIS (Netherlands)

Fieten, H; Spee, B; Ijzer, J; Kik, M J; Penning, L C; Kirpensteijn, J

Hepatocyte growth factor (HGF) and the proto-oncogenic receptor c-Met are implicated in growth, invasion, and metastasis in human cancer. Little information is available on the expression and role of both gene products in canine osteosarcoma. We hypothesized that the expression of c-Met is

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

Cryptotanshinone Regulates Androgen Synthesis through the ERK/c-Fos/CYP17 Pathway in Porcine Granulosa Cells

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Danfeng Ye

2017-01-01

Full Text Available The aim of the study is to investigate the molecular mechanism behind androgen reduction in porcine granulosa cells (pGCs with Salvia miltiorrhiza Bunge extract cryptotanshinone. PGCs were isolated from porcine ovaries and identified. Androgen excess model of the pGCs was induced with the MAPK inhibitor PD98059 and then treated with cryptotanshinone. The testosterone level was measured by radioimmunoassay in the culture media. The protein levels of P-ERK1/2, c-Fos, and CYP17 in the cells were measured by western blot. Cryptotanshinone decreased the concentration of testosterone and the protein level of CYP17 and increased the protein levels of P-ERK1/2 and c-Fos in the androgen excess mode. After the c-Fos gene was silenced by infection with c-Fos shRNA lentivirus, we measured the mRNA expression by quantitative RT-PCR and protein level by western blot of P-ERK1/2, c-Fos, and CYP17. This showed that the mRNA expression and protein level of P-ERK1/2 and c-Fos were significantly reduced in the shRNA–c-Fos group compared to the scrambled group, while those of CYP17 were significantly increased. So we concluded that cryptotanshinone can significantly reduce the androgen excess induced by PD98059 in pGCs. The possible molecular mechanism for this activity is regulating the ERK/c-Fos/CYP17 pathway.

In vivo correlation between c-Fos expression and corticotroph stimulation by adrenocorticotrophic hormone secretagogues in rat anterior pituitary gland.

Science.gov (United States)

Takigami, Shu; Fujiwara, Ken; Kikuchi, Motoshi; Yashiro, Takashi

2008-03-01

In the anterior pituitary gland, c-Fos expression is evoked by various stimuli. However, whether c-Fos expression is directly related to the stimulation of anterior pituitary cells by hypothalamic secretagogues is unclear. To confirm whether the reception of hormone-releasing stimuli evokes c-Fos expression in anterior pituitary cells, we have examined c-Fos expression of anterior pituitary glands in rats administered with synthetic corticotrophin-releasing hormone (CRH) intravenously or subjected to restraint stress. Single intravenous administration of CRH increases the number of c-Fos-expressing cells, and this number does not change even if the dose is increased. Double-immunostaining has revealed that most of the c-Fos-expressing cells contain adrenocorticotrophic hormone (ACTH); corticotrophs that do not express c-Fos in response to CRH have also been found. However, restraint stress evokes c-Fos expression in most of the corticotrophs and in a partial population of lactotrophs. These results suggest that c-Fos expression increases in corticotrophs stimulated by ACTH secretagogues, including CRH. Furthermore, we have found restricted numbers of corticotrophs expressing c-Fos in response to CRH. Although the mechanism underlying the different responses to CRH is not apparent, c-Fos is probably a useful immunohistochemical marker for corticotrophs stimulated by ACTH secretagogues.

Expression of c-fos and c-jun proteins in the marginal division of the rat striatum during learning and memory training

Institute of Scientific and Technical Information of China (English)

BAO Xin-min; SHU Si-yun; WANG Hong

2005-01-01

Background A new brain region, the marginal division (MrD), was discovered at the caudal margin of the neostriatum. The MrD was shown to be involved in learning and memory in the rat. The aim of this study was to investigate the expression of the immediate-early genes c-fos and c-jun in the MrD of the striatum during learning and memory processes in the rat, immunocytochemical and Western blot methods were used to examine Y-maze trained rats.Methods The rats were divided into three groups, namely the training, pseudotraining, and control groups. After Y-maze training, the expression of the immediate-early genes c-fos and c-jun in the MrD of the rats was investigated using immunocytochemical and Western blot methods. Results After one hour of Y-maze training, the expression of c-jun and c-fos proteins was significantly enhanced in the MrD; the c-jun protein, in particular, was more intensely expressed in this region than in other parts of the striatum. The expression of these two proteins in the training group was significantly higher than in the pseudotraining and control groups. In addition, positive expression was also found in the hippocampus, cingulum cortex, thalamus, and in other areas. Western blot disclosed two immunoreactive bands for the anti-c-fos antibody (47 kD and 54 kD) and two immunoreactive bands for the anti-c-jun antibody (39 kD and 54 kD). Conclusions These results indicate that the immediate-early genes c-fos and c-jun participate in signal transduction during the learning and memory processes associated with Y-maze training in rats.

Resveratrol stimulates c-Fos gene transcription via activation of ERK1/2 involving multiple genetic elements.

Science.gov (United States)

Thiel, Gerald; Rössler, Oliver G

2018-06-05

The polyphenol resveratrol is found in many plant and fruits and is a constituent of our diet. Resveratrol has been proposed to have chemopreventive and anti-inflammatory activities. On the cellular level, resveratrol activates stimulus-regulated transcription factors. To identify resveratrol-responsive elements within a natural gene promoter, the molecular pathway leading to c-Fos gene expression by resveratrol was dissected. The c-Fos gene encodes a basic region leucine zipper transcription factor and is a prototype of an immediate-early gene that is regulated by a wide range of signaling molecules. We analyzed chromatin-integrated c-Fos promoter-luciferase reporter genes where transcription factor binding sites were destroyed by point mutations or deletion mutagenesis. The results show that mutation of the binding sites for serum response factor (SRF), activator protein-1 (AP-1) and cAMP response element binding protein (CREB) significantly reduced reporter gene transcription following stimulation of the cells with resveratrol. Inactivation of the binding sites for signal transducer and activator of transcription (STAT) or ternary complex factors did not influence resveratrol-regulated c-Fos promoter activity. Thus, the c-Fos promoter contains three resveratrol-responsive elements, the cAMP response element (CRE), and the binding sites for SRF and AP-1. Moreover, we show that the transcriptional activation potential of the c-Fos protein is increased in resveratrol-stimulated cells, indicating that the biological activity of c-Fos is elevated by resveratrol stimulation. Pharmacological and genetic experiments revealed that the protein kinase ERK1/2 is the signal transducer that connects resveratrol treatment with the c-Fos gene. Copyright © 2018 Elsevier B.V. All rights reserved.

Pattern of c-Fos expression induced by tail suspension test in the mouse brain

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Kentaro Hiraoka

2017-06-01

Full Text Available The tail suspension test (TST has been widely used as a screening assay for antidepressant drugs. However, the neural substrates underlying the stress response and antidepressant-like effect during the TST remain largely unknown despite the prevalence of this test. In the present study, we used immunohistochemistry to examine alterations in c-Fos expression as a measure of neuronal activity in the mouse brain after acute administration of the antidepressant drugs nortriptyline or escitalopram (or saline as a control with or without a subsequent TST session. We found that without the TST session, nortriptyline administration enhanced the density of c-Fos-immunoreactive cells in regions of the central extended amygdala, paraventricular hypothalamic nucleus, and relevant regions of the brain stem, whereas escitalopram did not change c-Fos expression in any region. Following the TST in the absence of antidepressant drugs, we observed a significant increase in c-Fos-positive cell density in a number of brain regions within the limbic telencephalon, hypothalamus, and brain stem. We detected a statistically significant interaction using an analysis of variance between the main effects of the drug and stress response in four regions: the infralimbic cortex, lateral septal nucleus (intermediate part, ventrolateral preoptic nucleus, and solitary nucleus. Following the TST, escitalopram but not nortriptyline increased c-Fos-positive cell density in the infralimbic cortex and ventrolateral preoptic nucleus, whereas nortriptyline but not escitalopram increased c-Fos expression in the solitary nucleus. Both antidepressants significantly increased c-Fos expression in the lateral septal nucleus (intermediate part. The present results indicate that neuronal activity increases in septo-hypothalamic regions and related structures, especially the lateral septal nucleus, following administration of drugs producing an antidepressant-like effect in mice subjected to

Transcriptional regulation of BRD7 expression by Sp1 and c-Myc

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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

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

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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).

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.

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.

C-fos protein expression in central nervous system. Effects of acute whole-body irradiation

International Nuclear Information System (INIS)

Martin, C.; Chollat, S.; Mahfoudi, H.; Lambert, F.; Baille Le Crom, V.; Fatome, M.

1995-01-01

Study of c-Fos protein expression in the rat striatum after gamma or (neutron-gamma) irradiation was carried on. c-Fos protein is expressed one hour after gamma exposure at the dose of 15 Gy but specificity of the response must be verified. (author)

c-fos/c-jun expression and AP-1 activation in skin fibroblasts from centenarians.

Science.gov (United States)

Grassilli, E; Bellesia, E; Salomoni, P; Croce, M A; Sikora, E; Radziszewska, E; Tesco, G; Vergelli, M; Latorraca, S; Barbieri, D; Fagiolo, U; Santacaterina, S; Amaducci, L; Tiozzo, R; Sorbi, S; Franceschi, C

1996-09-13

In vitro replicative senescence is characterized by an irreversible growth arrest due to the inability of the cell to induce some key regulators of cell cycle progression, such as c-fos and AP-1, in response to mitogenic stimuli. In vitro replicative senescence and in vivo aging have been assumed to be two related phenomena, likely controlled by overlapping or interacting genes. As a corollary, fibroblasts from centenarians, which have undergone a long process of senescence in vivo should have very limited proliferative capability. On the contrary, in a previous work we found that fibroblasts from centenarians exhibited the same capacity to respond to different mitogenic stimuli as fibroblasts from young donors. Here we provide evidences that the well preserved proliferative response is likely due to the fact that some pivotal regulators- c-fos, c-jun and AP-1-are still fully inducible, despite a long process of in vivo senescence. Our data therefore suggest that in vivo and in vitro aging are separate phenomena whose possible relationships, if any, have to be ascertained very carefully.

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

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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.

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...

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.

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

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.

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.

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

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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.

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

Expression of c-fos gene in central nervous system of adult medaka (Oryzias latipes) after hypergravity stimulation

Science.gov (United States)

Shimomura, S.; Ijiri, K.

The immediate-early genes serve as useful neurobiological tools for mapping brain activity induced by a sensory stimulation. In this study, we have examined brain activity related to gravity perception of medaka (Oryzias latipes) by use of c-fos. The gene, which is homologous to the c-fos genes of other vertebrates, was identified in medaka. Functionally important domains are highly conserved among all the vertebrate species analyzed. Intraperitoneal administration of kainic acid transiently induced the c-fos mRNAs in medaka brain. The results indicate that the expression of c-fos can be utilized as a suitable anatomical marker for the increased neural activities in the central nervous system of medaka. Fish were continuously exposed to 3G hypergravity by centrifugation. Investigation of c-fos mRNA expression showed that c-fos mRNA significantly increased 30 minutes after a start of 3G exposure. The distribution of its transcripts within brains was analyzed by an in situ hybridization method. The 3G-treated medakas displayed c-fos positive cells in their brainstem regions, which are related to vestibular function, such as torus semicircularis, posterior octavu nucleus, nucleus tangentialis and inferior olive. Our results established the method to trace the activated area in the fish brain following gravity stimulation. The method will be a useful tool for understanding gravity perception in the brain.

Characterization of E-cadherin-dependent and -independent events in a new model of c-Fos-mediated epithelial-mesenchymal transition

International Nuclear Information System (INIS)

Mejlvang, Jakob; Kriajevska, Marina; Berditchevski, Fedor; Bronstein, Igor; Lukanidin, Eugene M.; Pringle, J. Howard; Mellon, J. Kilian; Tulchinsky, Eugene M.

2007-01-01

Fos proteins have been implicated in control of tumorigenesis-related genetic programs including invasion, angiogenesis, cell proliferation and apoptosis. In this study, we demonstrate that c-Fos is able to induce mesenchymal transition in murine tumorigenic epithelial cell lines. Expression of c-Fos in MT1TC1 cells led to prominent alterations in cell morphology, increased expression of mesenchymal markers, vimentin and S100A4, DNA methylation-dependent down-regulation of E-cadherin and abrogation of cell-cell adhesion. In addition, c-Fos induced a strong β-catenin-independent proliferative response in MT1TC1 cells and stimulated cell motility, invasion and adhesion to different extracellular matrix proteins. To explore whether loss of E-cadherin plays a role in c-Fos-mediated mesenchymal transition, we expressed wild-type E-cadherin and two different E-cadherin mutants in MT1TC1/c-fos cells. Expression of wild-type E-cadherin restored epithelioid morphology and enhanced cellular levels of catenins. However, exogenous E-cadherin did not influence expression of c-Fos-dependent genes, only partly suppressed growth of MT1TC1/c-fos cells and produced no effect on c-Fos-stimulated cell motility and invasion in matrigel. On the other hand, re-expression of E-cadherin specifically negated c-Fos-induced adhesion to collagen type I, but not to laminin or fibronectin. Of interest, mutant E-cadherin which lacks the ability to form functional adhesive complexes had an opposite, potentiating effect on cell adhesion to collagen I. These data suggest that cell adhesion to collagen I is regulated by the functional state of E-cadherin. Overall, our data demonstrate that, with the exception of adhesion to collagen I, c-Fos is dominant over E-cadherin in relation to the aspects of mesenchymal transition assayed in this study

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.

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}.

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

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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

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

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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

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

Acute suppression, but not chronic genetic deficiency, of c-fos gene expression impairs long-term memory in aversive taste learning.

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Yasoshima, Yasunobu; Sako, Noritaka; Senba, Emiko; Yamamoto, Takashi

2006-05-02

Several lines of evidence have indicated that the establishment of long-term memory requires protein synthesis, including the synthesis of immediate-early gene products. Although the anatomical expression patterns of the c-fos gene, a transcription factor-encoding immediate-early gene, in conditioned taste aversion (CTA) are well documented, the functional roles of c-fos gene expression and Fos-mediated transcription remain to be clarified. Using the antisense oligodeoxynucleotide (AS-ODN) method in rats and gene-targeting knockout techniques in mice (c-fos(-/-) mice), we examined the roles of c-fos gene expression in the acquisition, retrieval, and retention of CTA. Preconditioning microinfusion of AS-ODN directed against c-fos mRNA (c-fos AS-ODN) into the parabrachial nucleus (PBN) impaired the acquisition, whereas infusion of control ODNs consisting of a randomized or inverted base order had no effect. Microinfusion of c-fos AS-ODN into either the amygdala or insular cortex did not impair the acquisition, whereas it attenuated the retention. Retrieval and subsequent retention of an acquired CTA were not disrupted by c-fos AS-ODN infusion into the PBN or amygdala. Microinfusion of another AS-ODN directed against zif268 (egr-1, krox-24, NGFI-A) mRNA into the PBN or amygdala did not affect the acquisition and retention. The genetic deficiency in c-fos(-/-) mice caused normal acquisition and retention. The present results suggest that the Fos-mediated gene transcription in the PBN, amygdala, or insular cortex plays critical roles in the acquisition and/or consolidation, but not the retrieval, of long-term taste memory; nevertheless, some other factors could compensate CTA mechanism when Fos-mediated transcription is not available.

Astroglial c-Myc overexpression predisposes mice to primary malignant gliomas

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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....

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.

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

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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

Activations of c-fos/c-jun signaling are involved in the modulation of hypothalamic superoxide dismutase (SOD) and neuropeptide Y (NPY) gene expression in amphetamine-mediated appetite suppression

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Hsieh, Y.-S.; Yang, S.-F.; Chiou, H.-L.; Kuo, D.-Y.

2006-01-01

Amphetamine (AMPH) is known as an anorectic agent. The mechanism underlying the anorectic action of AMPH has been attributed to its inhibitory action on hypothalamic neuropeptide Y (NPY), an appetite stimulant in the brain. This study was aimed to examine the molecular mechanisms behind the anorectic effect of AMPH. Results showed that AMPH treatment decreased food intake, which was correlated with changes of NPY mRNA level, but increased c-fos, c-jun and superoxide dismutase (SOD) mRNA levels in hypothalamus. To determine if c-fos or c-jun was involved in the anorectic response of AMPH, infusions of antisense oligonucleotide into the brain were performed at 1 h before daily AMPH treatment in freely moving rats, and the results showed that c-fos or c-jun knockdown could block this anorectic response and restore NPY mRNA level. Moreover, c-fos or c-jun knockdown could partially block SOD mRNA level that might involve in the modulation of NPY gene expression. It was suggested that c-fos/c-jun signaling might involve in the central regulation of AMPH-mediated feeding suppression via the modulation of NPY gene expression

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

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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

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

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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.

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

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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...

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

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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.

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

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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.

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.

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

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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.

Activation of the CREB/c-Fos Pathway during Long-Term Synaptic Plasticity in the Cerebellum Granular Layer

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Daniela Gandolfi

2017-06-01

Full Text Available The induction of long-term potentiation and depression (LTP and LTD is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these mechanisms remained unclear. Here, we have investigated phosphorylation of the cAMP-responsive element binding protein (CREB and activation of the immediate early gene c-Fos pathway following the induction of synaptic plasticity by theta-burst stimulation (TBS in acute cerebellar slices. LTP and LTD were localized using voltage-sensitive dye imaging (VSDi. At two time points following TBS (15 min and 120 min, corresponding to the early and late phases of plasticity, slices were fixed and processed to evaluate CREB phosphorylation (P-CREB and c-FOS protein levels, as well as Creb and c-Fos mRNA expression. High levels of P-CREB and Creb/c-Fos were detected before those of c-FOS, as expected if CREB phosphorylation triggered gene expression followed by protein synthesis. No differences between control slices and slices stimulated with TBS were observed in the presence of an N-methyl-D-aspartate receptor (NMDAR antagonist. Interestingly, activation of the CREB/c-Fos system showed a relevant degree of colocalization with long-term synaptic plasticity. These results show that NMDAR-dependent plasticity at the cerebellum input stage bears about transcriptional and post-transcriptional processes potentially contributing to cerebellar learning and memory consolidation.

The structural determinants responsible for c-Fos protein proteasomal degradation differ according to the conditions of expression.

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Ferrara, Patrizia; Andermarcher, Elisabetta; Bossis, Guillaume; Acquaviva, Claire; Brockly, Frédérique; Jariel-Encontre, Isabelle; Piechaczyk, Marc

2003-03-13

c-fos gene is expressed constitutively in a number of tissues as well as in certain tumor cells and is inducible, in general rapidly and transiently, in virtually all other cell types by a variety of stimuli. Its protein product, c-Fos, is a short-lived transcription factor that heterodimerizes with various protein partners within the AP-1 transcription complex via leucine zipper/leucine zipper interactions for binding to specific DNA sequences. It is mostly, if not exclusively, degraded by the proteasome. To localize the determinant(s) responsible for its instability, we have conducted a genetic analysis in which the half-lives of c-Fos mutants and chimeras made with the stable EGFP reporter protein were compared under two experimental conditions taken as example of continous and inducible expression. Those were constitutive expression in asynchronously growing Balb/C 3T3 mouse embryo fibroblasts and transient induction in the same cells undergoing the G0/G1 phase transition upon stimulation by serum. Our work shows that c-Fos is degraded faster in synchronous- than in asynchronous cells. This difference in turnover is primarily accounted for by several mechanisms. First, in asynchronous cells, a unique C-terminal destabilizer is active whereas, in serum-stimulated cells two destabilizers located at both extremities of the protein are functional. Second, heterodimerization and/or binding to DNA accelerates protein degradation only during the G0/G1 phase transition. Adding another level of complexity to turnover control, phosphorylation at serines 362 and 374, which are c-Fos phosphorylation sites largely modified during the G0/G1 phase transition, stabilizes c-Fos much more efficiently in asynchronous than in serum-stimulated cells. In both cases, the reduced degradation rate is due to inhibition of the activity of the C-terminal destabilizer. However, in serum-stimulated cells, this effect is partially masked by the activation of the N-terminal destabilizer and

'Fluorescent Cell Chip' for immunotoxicity testing: Development of the c-fos expression reporter cell lines

International Nuclear Information System (INIS)

Trzaska, Dominika; Zembek, Patrycja; Olszewski, Maciej; Adamczewska, Violetta; Ulleras, Erik; Dastych, JarosIaw

2005-01-01

The Fluorescent Cell Chip for in vitro immunotoxicity testing employs cell lines derived from lymphocytes, mast cells, and monocytes-macrophages transfected with various EGFP cytokine reporter gene constructs. While cytokine expression is a valid endpoint for in vitro immunotoxicity screening, additional marker for the immediate-early response gene expression level could be of interest for further development and refinement of the Fluorescent Cell Chip. We have used BW.5147.3 murine thymoma transfected with c-fos reporter constructs to obtain reporter cell lines expressing ECFP under the control of murine c-fos promoter. These cells upon serum withdrawal and readdition and incubation with heavy metal compounds showed paralleled induction of c-Fos expression as evidenced by Real-Time PCR and ECFP fluorescence as evidenced by computer-supported fluorescence microscopy. In conclusion, we developed fluorescent reporter cell lines that could be employed in a simple and time-efficient screening assay for possible action of chemicals on c-Fos expression in lymphocytes. The evaluation of usefulness of these cells for the Fluorescent Cell Chip-based detection of immunotoxicity will require additional testing with a larger number of chemicals

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.

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

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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

MicroRNA-490-5p inhibits proliferation of bladder cancer by targeting c-Fos

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Li, Shiqi; Xu, Xianglai; Xu, Xin; Hu, Zhenghui; Wu, Jian; Zhu, Yi; Chen, Hong; Mao, Yeqing; Lin, Yiwei; Luo, Jindan; Zheng, Xiangyi; Xie, Liping

2013-01-01

Highlights: •We examined the level of miR-490-5p in bladder cancer tissues and three cancer cell lines. •We are the first to show the function of miR-490-5p in bladder cancer. •We demonstrate c-Fos may be a target of miR-490-5p. -- Abstract: MicroRNAs (miRNAs) are non-protein-coding sequences that play a crucial role in tumorigenesis by negatively regulating gene expression. Here, we found that miR-490-5p is down-regulated in human bladder cancer tissue and cell lines compared to normal adjacent tissue and a non-malignant cell line. To better characterize the function of miR-490-5p in bladder cancer, we over-expressed miR-490-5p in bladder cancer cell lines with chemically synthesized mimics. Enforced expression of miR-490-5p in bladder cancer cells significantly inhibited the cell proliferation via G1-phase arrest. Further studies found the decreased c-Fos expression at both mRNA and protein levels and Luciferase reporter assays demonstrated that c-Fos is a direct target of miR-490-5p in bladder cancer. These findings indicate miR-490-5p to be a novel tumor suppressor of bladder cancer cell proliferation through targeting c-Fos

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

Effects of Electrical Stimulation of the Rat Vestibular Labyrinth on c-Fos Expression in the Hippocampus.

Science.gov (United States)

Hitier, Martin; Sato, Go; Zhang, Yan-Feng; Besnard, Stephane; Smith, Paul F

2018-04-22

Several studies have demonstrated that electrical activation of the peripheral vestibular system can evoke field potential, multi-unit neuronal activity and acetylcholine release in the hippocampus (HPC). However, no study to date has employed the immediate early gene protein, c-Fos, to investigate the distribution of activation of cells in the HPC following electrical stimulation of the vestibular system. We found that vestibular stimulation increased the number of animals expressing c-Fos in the dorsal HPC compared to sham control rats (P ≤ 0.02), but not in the ventral HPC. c-Fos was also expressed in an increased number of animals in the dorsal dentate gyrus (DG) compared to sham control rats (P ≤ 0.0001), and to a lesser extent in the ventral DG (P ≤ 0.006). The results of this study show that activation of the vestibular system results in a differential increase in the expression of c-Fos across different regions of the HPC. Copyright © 2018 Elsevier B.V. All rights reserved.

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

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.

C-fos expression in the pons and medulla of the cat during carbachol-induced active sleep.

Science.gov (United States)

Yamuy, J; Mancillas, J R; Morales, F R; Chase, M H

1993-06-01

Microinjection of carbachol into the rostral pontine tegmentum of the cat induces a state that is comparable to naturally occurring active (REM, rapid eye movement) sleep. We sought to determine, during this pharmacologically induced behavioral state, which we refer to as active sleep-carbachol, the distribution of activated neuron within the pons and medulla using c-fos immunocytochemistry as a functional marker. Compared with control cats, which were injected with saline, active sleep-carbachol cats exhibited higher numbers of c-fos-expressing neurons in (1) the medial and portions of the lateral reticular formation of the pons and medulla, (2) nuclei in the dorsolateral rostral pons, (3) various raphe nuclei, including the dorsal, central superior, magnus, pallidus, and obscurus, (4) the medial and lateral vestibular, prepositus hypoglossi, and intercalatus nuclei, and (5) the abducens nuclei. On the other hand, the mean number of c-fos-expressing neurons found in the masseter, facial, and hypoglossal nuclei was lower in carbachol-injected than in control cats. The data indicate that c-fos expression can be employed as a marker of state-dependent neuronal activity. The specific sites in which there were greater numbers of c-fos-expressing neurons during active sleep-carbachol are discussed in relation to the state of active sleep, as well as the functional role that these sites play in generating the various physiological patterns of activity that occur during this state.

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.

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

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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

Nonlinear development of the populations of neurons expressing c-Fos under sustained electrical intracochlear stimulation in the rat auditory brainstem.

Science.gov (United States)

Rosskothen-Kuhl, Nicole; Illing, Robert-Benjamin

2010-08-06

The immediate-early-gene c-fos is among the first genes to be expressed following sensory-invoked neuronal activity. Its gene product c-Fos forms the limiting monomer of the heterodimeric activator protein-1 transcription factor that triggers various genes involved in neuroplastic remodeling. This study investigated the pattern of c-Fos expression in anteroventral (AVCN) and dorsal cochlear nucleus (DCN) and central inferior colliculus (CIC) after 45 min, 73 min, 2 h, 3:15 h and 5 h of unilateral electrical intracochlear stimulation (EIS) at 50 Hz in anaesthetized rats. Following EIS, tonotopic c-Fos expression was observed for each stimulation time in ipsilateral AVCN, DCN bilaterally, and contralateral CIC. By counting c-Fos positive nuclei, we discovered temporal non-linearities in the size of the respective population of c-Fos expressing neurons. In all regions investigated, the populations significantly increased from 73 min to 2 h but decreased towards 3:15 h. In AVCN, the number rose again by 5 h of EIS. Remarkably, the same was noted for neurons with large nuclei in deep DCN. In both regions, the population of responsive neurons shifted spatially: In central AVCN, the density of c-Fos positive cells increased significantly from 2 to 5h with medial and lateral regions remaining unchanged. In DCN, the density of large c-Fos positive nuclei fell in the upper and rose in the deep layers from 45 min to 5h of EIS. In conclusion, spatiotemporally varying recruitments of neuronal subpopulations into cellular networks responding to specific patterns of sensory activity take place in the auditory brainstem. Copyright 2010 Elsevier B.V. All rights reserved.

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

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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.

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.

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

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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.

The hallucinogen d-lysergic acid diethylamide (d-LSD) induces the immediate-early gene c-Fos in rat forebrain.

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Frankel, Paul S; Cunningham, Kathryn A

2002-12-27

The hallucinogen d-lysergic acid diethylamide (d-LSD) evokes dramatic somatic and psychological effects. In order to analyze the neural activation induced by this unique psychoactive drug, we tested the hypothesis that expression of the immediate-early gene product c-Fos is induced in specific regions of the rat forebrain by a relatively low, behaviorally active, dose of d-LSD (0.16 mg/kg, i.p.); c-Fos protein expression was assessed at 30 min, and 1, 2 and 4 h following d-LSD injection. A time- and region-dependent expression of c-Fos was observed with a significant increase (PLSD administration. These data demonstrate a unique pattern of c-Fos expression in the rat forebrain following a relatively low dose of d-LSD and suggest that activation of these forebrain regions contributes to the unique behavioral effects of d-LSD. Copyright 2002 Elsevier Science B.V.

Spatiotemporal differences in the c-fos pathway between C57BL/6J and DBA/2J mice following flurothyl-induced seizures: A dissociation of hippocampal Fos from seizure activity.

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Kadiyala, Sridhar B; Papandrea, Dominick; Tuz, Karina; Anderson, Tara M; Jayakumar, Sachidhanand; Herron, Bruce J; Ferland, Russell J

2015-01-01

Significant differences in seizure characteristics between inbred mouse strains highlight the importance of genetic predisposition to epilepsy. Here, we examined the genetic differences between the seizure-resistant C57BL/6J (B6) mouse strain and the seizure-susceptible DBA/2J (D2) strain in the phospho-Erk and Fos pathways to examine seizure-induced neuronal activity to uncover potential mechanistic correlates to these disparate seizure responsivities. Expression of neural activity markers was examined following 1, 5, or 8 seizures, or after 8 seizures, a 28 day rest period, and a final flurothyl rechallenge. Two brain regions, the hippocampus and ventromedial nucleus of the hypothalamus (VMH), had significantly different Fos expression profiles following seizures. Fos expression was highly robust in B6 hippocampus following one seizure and remained elevated following multiple seizures. Conversely, there was an absence of Fos (and phospho-Erk) expression in D2 hippocampus following one generalized seizure that increased with multiple seizures. This lack of Fos expression occurred despite intracranial electroencephalographic recordings indicating that the D2 hippocampus propagated ictal discharge during the first flurothyl seizure suggesting a dissociation of seizure discharge from Fos and phospho-Erk expression. Global transcriptional analysis confirmed a dysregulation of the c-fos pathway in D2 mice following 1 seizure. Moreover, global analysis of RNA expression differences between B6 and D2 hippocampus revealed a unique pattern of transcripts that were co-regulated with Fos in D2 hippocampus following 1 seizure. These expression differences could, in part, account for D2's seizure susceptibility phenotype. Following 8 seizures, a 28 day rest period, and a final flurothyl rechallenge, ∼85% of B6 mice develop a more complex seizure phenotype consisting of a clonic-forebrain seizure that uninterruptedly progresses into a brainstem seizure. This seizure phenotype

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

Analysis of Myc-induced histone modifications on target chromatin.

Directory of Open Access Journals (Sweden)

Francesca Martinato

Full Text Available The c-myc proto-oncogene is induced by mitogens and is a central regulator of cell growth and differentiation. The c-myc product, Myc, is a transcription factor that binds a multitude of genomic sites, estimated to be over 10-15% of all promoter regions. Target promoters generally pre-exist in an active or poised chromatin state that is further modified by Myc, contributing to fine transcriptional regulation (activation or repression of the afferent gene. Among other mechanisms, Myc recruits histone acetyl-transferases to target chromatin and locally promotes hyper-acetylation of multiple lysines on histones H3 and H4, although the identity and combination of the modified lysines is unknown. Whether Myc dynamically regulates other histone modifications (or marks at its binding sites also remains to be addressed. Here, we used quantitative chromatin immunoprecipitation (qChIP to profile a total of 24 lysine-acetylation and -methylation marks modulated by Myc at target promoters in a human B-cell line with a regulatable c-myc transgene. Myc binding promoted acetylation of multiple lysines, primarily of H3K9, H3K14, H3K18, H4K5 and H4K12, but significantly also of H4K8, H4K91 and H2AK5. Dimethylation of H3K79 was also selectively induced at target promoters. A majority of target promoters showed co-induction of multiple marks - in various combinations - correlating with recruitment of the two HATs tested (Tip60 and HBO1, incorporation of the histone variant H2A.Z and transcriptional activation. Based on this and previous findings, we surmise that Myc recruits the Tip60/p400 complex to achieve a coordinated histone acetylation/exchange reaction at activated promoters. Our data are also consistent with the additive and redundant role of multiple acetylation events in transcriptional activation.

Brain c-fos expression patterns induced by emotional stressors differing in nature and intensity.

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Úbeda-Contreras, Jesús; Marín-Blasco, Ignacio; Nadal, Roser; Armario, Antonio

2018-06-01

Regardless of its particular nature, emotional stressors appear to elicit a widespread and roughly similar brain activation pattern as evaluated by c-fos expression. However, their behavioral and physiological consequences may strongly differ. Here we addressed in adult male rats the contribution of the intensity and the particular nature of stressors by comparing, in a set of brain areas, the number of c-fos expressing neurons in response to open-field, cat odor or immobilization on boards (IMO). These are qualitatively different stressors that are known to differ in terms of intensity, as evaluated by biological markers. In the present study, plasma levels of the adrenocorticotropic hormone (ACTH) demonstrated that intensity increases in the following order: open-field, cat odor and IMO. Four different c-fos activation patterns emerged among all areas studied: (i) positive relationship with intensity (posterior-dorsal medial amygdala, dorsomedial hypothalamus, lateral septum ventral and paraventricular nucleus of the hypothalamus), (ii) negative relationship with intensity (cingulate cortex 1, posterior insular cortex, dorsal striatum, nucleus accumbens and some subdivisions of the hippocampal formation); (iii) activation not dependent on the intensity of the stressor (prelimbic and infralimbic cortex and lateral and basolateral amygdala); and (iv) activation specifically associated with cat odor (ventromedial amygdala and ventromedial hypothalamus). Histone 3 phosphorylation at serine 10, another neuronal activation marker, corroborated c-fos results. Summarizing, deepest analysis of the brain activation pattern elicit by emotional stressor indicated that, in spite of activating similar areas, each stressor possess their own brain activation signature, mediated mainly by qualitative aspects but also by intensity.

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

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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.

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

Prostaglandin E2 and the protein kinase A pathway mediate arachidonic acid induction of c-fos in human prostate cancer cells

Science.gov (United States)

Chen, Y.; Hughes-Fulford, M.

2000-01-01

Arachidonic acid (AA) is the precursor for prostaglandin E2 (PGE2) synthesis and increases growth of prostate cancer cells. To further elucidate the mechanisms involved in AA-induced prostate cell growth, induction of c-fos expression by AA was investigated in a human prostate cancer cell line, PC-3. c-fos mRNA was induced shortly after addition of AA, along with a remarkable increase in PGE2 production. c-fos expression and PGE2 production induced by AA was blocked by a cyclo-oxygenase inhibitor, flurbiprofen, suggesting that PGE2 mediated c-fos induction. Protein kinase A (PKA) inhibitor H-89 abolished induction of c-fos expression by AA, and partially inhibited PGE2 production. Protein kinase C (PKC) inhibitor GF109203X had no significant effect on c-fos expression or PGE2 production. Expression of prostaglandin (EP) receptors, which mediate signal transduction from PGE2 to the cells, was examined by reverse transcription polymerase chain reaction in several human prostate cell lines. EP4 and EP2, which are coupled to the PKA signalling pathway, were expressed in all cells tested. Expression of EP1, which activates the PKC pathway, was not detected. The current study showed that induction of the immediate early gene c-fos by AA is mediated by PGE2, which activates the PKA pathway via the EP2/4 receptor in the PC-3 cells.

Prolonged induction of c-fos in neuropeptide Y- and somatostatin-immunoreactive neurons of the rat dentate gyrus after electroconvulsive stimulation

DEFF Research Database (Denmark)

Woldbye, D P; Greisen, M H; Bolwig, T G

1996-01-01

Induction of c-fos mRNA and Fos was studied in the hilus and granular layer of the dentate gyrus at various times up to 24 h after single electroconvulsive stimulation (ECS) using in situ hybridization and immunocytochemistry. In both areas of the dentate gyrus, a prominent induction of c-fos m...

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

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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.

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

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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.

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.

[The expression of the c-fos gene in the brain of mice in the dynamic acquisition of defensive behavioral habits].

Science.gov (United States)

Anokhin, K V; Riabinin, A E; Sudakov, K V

2000-01-01

Levels of c-fos mRNA expression in mouse cerebral cortex and hippocampus at different stages of footshock escape and avoidance learning were studied by Northern hydridization. In the first series of experiments a mouse was presented with 30 electric footshock daily in a chamber where it could escape from the floor by jumping on the safe platform attached to the wall. A large increase in c-fos mRNA level in the cerebral cortex and hippocampus was observed during the first day of training. Mice that were trained for 9 consecutive days and acquired a footshock escape reaction showed no elevation of c-fos expression in the brain as compared to the quiet control group. In the second series of experiments the levels of c-fos expression were compared in individual mice trained to avoid the footshock by jumping on the platform in response to an auditory conditioned stimulus. Mice which acquired avoidance behavior more rapidly had lower c-fos mRNA levels than slow learners. There was no such to difference between the corresponding yoked control groups which consisted of animals matched the rapid and slow learners by the number of footshocks received. It is concluded that achievement of adaptive results in the course of learning leads to a suppression of further c-fos induction by motivational excitation.

Environmental enrichment and gut inflammation modify stress-induced c-Fos expression in the mouse corticolimbic system.

Directory of Open Access Journals (Sweden)

Florian Reichmann

Full Text Available Environmental enrichment (EE has a beneficial effect on rodent behaviour, neuronal plasticity and brain function. Although it may also improve stress coping, it is not known whether EE influences the brain response to an external (psychological stressor such as water avoidance stress (WAS or an internal (systemic stressor such as gastrointestinal inflammation. This study hence explored whether EE modifies WAS-induced activation of the mouse corticolimbic system and whether this stress response is altered by gastritis or colitis. Male C67BL/6N mice were housed under standard or enriched environment for 9 weeks, after which they were subjected to a 1-week treatment with oral iodoacetamide to induce gastritis or oral dextran sulfate sodium to induce colitis. Following exposure to WAS the expression of c-Fos, a marker of neuronal activation, was measured by immunocytochemistry. EE aggravated experimentally induced colitis, but not gastritis, as shown by an increase in the disease activity score and the colonic myeloperoxidase content. In the brain, EE enhanced the WAS-induced activation of the dentate gyrus and unmasked an inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression within this part of the hippocampus. Conversely, EE inhibited the WAS-evoked activation of the central amygdala and prevented the inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression in this region. EE, in addition, blunted the WAS-induced activation of the infralimbic cortex and attenuated the inhibitory effect of gastritis and colitis on WAS-evoked c-Fos expression in this area. These data reveal that EE has a region-specific effect on stress-induced c-Fos expression in the corticolimbic system, which is likely to improve stress resilience. The response of the prefrontal cortex - amygdala - hippocampus circuitry to psychological stress is also modified by the systemic stress of gut inflammation, and this interaction between external

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.

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

Science.gov (United States)

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.

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

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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

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

Primary structure of the human fgr proto-oncogene product p55/sup c-fgr/

Energy Technology Data Exchange (ETDEWEB)

Katamine, S.; Notario, V.; Rao, C.D.; Miki, T.; Cheah, M.S.C.; Tronick, S.R.; Robbins, K.C.

1988-01-01

Normal human c-fgr cDNA clones were constructed by using normal peripheral blood mononuclear cell mRNA as a template. Nucleotide sequence analysis of two such clones revealed a 1,587-base-pair-long open reading frame which predicted the primary amino acid sequence of the c-fgr translational product. Homology of this protein with the v-fgr translational product stretched from codons 128 to 516, where 32 differences among 388 codons were observed. Sequence similarity with human c-src, c-yes, and fyn translations products began at amino acid position 76 of the predicted c-fgr protein and extended nearly to its C-terminus. In contrast, the stretch of 75 amino acids at the N-terminus demonstrated a greatly reduced degree of relatedness to these same proteins. To verify the deduced amino acid sequence, antibodies were prepared against peptides representing amino- and carboxy-terminal regions of the predicted c-fgr translational product. Both antibodies specifically recognized a 55-kilodalton protein expressed in COS-1 cells transfected with a c-fgr cDNA expression plasmid. Moreover, the same protein was immunoprecipitated from an Epstein-Barr virus-infected Burkitt's lymphoma cell line which expressed c-fgr mRNA but not in its uninfected fgr mRNA-negative counterpart. These findings identified the 55-kilodalton protein as the product of the human fgr proto-oncogene.

Acute phencyclidine administration induces c-Fos-immunoreactivity in interneurons in cortical and subcortical regions

DEFF Research Database (Denmark)

Hervig, Mona E; Thomsen, Morten S; Kalló, Imre

2016-01-01

and thalamus of rats. A single dose of PCP (10mg/kg, s.c.) significantly increased total number of c-Fos-IR in: (1) the prelimbic, infralimbic, anterior cingulate, ventrolateral orbital, motor, somatosensory and retrosplenial cortices as well as the nucleus accumbens (NAc), field CA1 of the hippocampus (CA1......) field of hippocampus and mediodorsal thalamus (MD); (2) PV-IR cells in the ventrolateral orbitofrontal and retrosplenial cortices and CA1 field of hippocampus; and (3) CB-IR cells in the motor cortex. Overall, our data indicate that PCP activates a wide range of cortical and subcortical brain regions...... and subcortical areas, but whether such induction occurs in specific populations of GABAergic interneuron subtypes still remains to be established. We performed an immunohistochemical analysis of the PCP-induced c-Fos-immunoreactivity (IR) in parvalbumin (PV) and calbindin (CB) interneuron subtypes in the cortex...

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.

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

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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.

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.

Immediate-early gene response to repeated immobilization: Fos protein and arc mRNA levels appear to be less sensitive than c-fos mRNA to adaptation.

Science.gov (United States)

Ons, Sheila; Rotllant, David; Marín-Blasco, Ignacio J; Armario, Antonio

2010-06-01

Stress exposure resulted in brain induction of immediate-early genes (IEGs), considered as markers of neuronal activation. Upon repeated exposure to the same stressor, reduction of IEG response (adaptation) has been often observed, but there are important discrepancies in literature that may be in part related to the particular IEG and methodology used. We studied the differential pattern of adaptation of the IEGs c-fos and arc (activity-regulated cytoskeleton-associated protein) after repeated exposure to a severe stressor: immobilization on wooden boards (IMO). Rats repeatedly exposed to IMO showed reduced c-fos mRNA levels in response to acute IMO in most brain areas studied: the medial prefrontal cortex (mPFC), lateral septum (LS), medial amygdala (MeA), paraventricular nucleus of the hypothalamus (PVN) and locus coeruleus. In contrast, the number of neurons showing Fos-like immunoreactivity was only reduced in the MeA and the various subregions of the PVN. IMO-induced increases in arc gene expression were restricted to telencephalic regions and reduced by repeated IMO only in the mPFC. Double-labelling in the LS of IMO-exposed rats revealed that arc was expressed in only one-third of Fos+ neurons, suggesting two populations of Fos+ neurons. These data suggest that c-fos mRNA levels are more affected by repeated IMO than corresponding protein, and that arc gene expression does not reflect adaptation in most brain regions, which may be related to its constitutive expression. Therefore, the choice of a particular IEG and the method of measurement are important for proper interpretation of the impact of chronic repeated stress on brain activation.

Fisetin Inhibits Osteoclast Differentiation via Downregulation of p38 and c-Fos-NFATc1 Signaling Pathways

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Sik-Won Choi

2012-01-01

Full Text Available The prevention or therapeutic treatment of loss of bone mass is an important means of improving the quality of life for patients with disorders related to osteoclast-mediated bone loss. Fisetin, a flavonoid dietary ingredient found in the smoke tree (Continus coggygria, exhibits various biological activities, but its effect on osteoclast differentiation is unknown. In this study, fisetin dose-dependently inhibited the RANKL-induced osteoclast differentiation with downregulation of the activity or expression of p38, c-Fos, and NFATc1 signaling molecules. The p38/c-Fos/NFATc1-regulated expression of genes required for cell fusion and bone resorption, such as DC-STAMP and cathepsin K, was also inhibited by fisetin. Considering the rescue of fisetin's inhibitory action by NFATc1 over-expression, the cascade of p38-c-Fos-NFATc1 could be strongly involved in the inhibitory effect of fisetin on osteoclast differentiation. Furthermore, fisetin inhibited the bone-resorbing activity of mature osteoclasts. In conclusion, fisetin may be of use in the treatment of osteoclast-related disorders, including osteoporosis.

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

A dual-immunocytochemical method to localize c-fos protein in specific neurons based on their content of neuropeptides and connectivity

DEFF Research Database (Denmark)

Mikkelsen, J D; Larsen, P J; Sørensen, G G

1994-01-01

Enhanced expression of the immediate early gene c-fos has been used as a marker of cellular activation in many different neuronal pathways. We wished to determine the neurochemical content and the connectivity of neurons, in which expression of c-fos is induced. For this purpose, a dual...

c-Fos expression predicts long-term social memory retrieval in mice.

Science.gov (United States)

Lüscher Dias, Thomaz; Fernandes Golino, Hudson; Moura de Oliveira, Vinícius Elias; Dutra Moraes, Márcio Flávio; Schenatto Pereira, Grace

2016-10-15

The way the rodent brain generally processes socially relevant information is rather well understood. How social information is stored into long-term social memory, however, is still under debate. Here, brain c-Fos expression was measured after adult mice were exposed to familiar or novel juveniles and expression was compared in several memory and socially relevant brain areas. Machine Learning algorithm Random Forest was then used to predict the social interaction category of adult mice based on c-Fos expression in these areas. Interaction with a familiar co-specific altered brain activation in the olfactory bulb, amygdala, hippocampus, lateral septum and medial prefrontal cortex. Remarkably, Random Forest was able to predict interaction with a familiar juvenile with 100% accuracy. Activity in the olfactory bulb, amygdala, hippocampus and the medial prefrontal cortex were crucial to this prediction. From our results, we suggest long-term social memory depends on initial social olfactory processing in the medial amygdala and its output connections synergistically with non-social contextual integration by the hippocampus and medial prefrontal cortex top-down modulation of primary olfactory structures. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Synsepalum dulcificum extracts exhibit cytotoxic activity on human colorectal cancer cells and upregulate c-fos and c-jun early apoptotic gene expression

Directory of Open Access Journals (Sweden)

Jichang Seong

2018-01-01

Full Text Available Objective: To explore cytotoxicity of Synsepalum dulcificum (S. dulcificum Daniell (Sapotaceae on human colon cancer (HCT-116 and HT-29, human monocytic leukemia (THP-1 and normal (HDFn cell lines, and its effect on the expression of early apoptotic genes, c-fos and c-jun. Methods: Leaf, stem and berry of S. dulcificum were separately extracted by using 2 solvents, 10% ethanol (EtOH and 80% methanol (MeOH. PrestoBlue® cell viability assay and qRT-PCR assay were conducted to examine the above objectives respectively. Results: Stem MeOH, stem EtOH, and berry EtOH extracts of S. dulcificum were cytotoxic to HCT-116 and HT-29 human colon cancer cells. For HCT-116, IC50 values of these 3 extracts were not significantly different (P>0.05 from that of the positive control bleomycin (IC50 of 33.57 μg/mL, while for HT-29, IC50 values of these 3 extracts were significantly lower (P<0.05 than that of bleomycin (IC50 of 25.24 μg/mL. None of the extracts were cytotoxic to the THP-1 monocytic leukemia cells and HDFn normal human dermal fibroblasts. For both HCT-116 and HT-29, these extracts significantly up-regulated (P<0.05 the expression of c-fos and c-jun compared to the untreated negative control. Conclusions: The results of this study suggest that cytotoxicity of stem MeOH, stem EtOH, and berry EtOH extracts of S. dulcificum on HCT-116 and HT-29 colon cancer cells is due to the induced apoptosis which is caused by the up-regulation of the expression of early apoptotic genes, c-fos and c-jun.

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

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.

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

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.

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

Science.gov (United States)

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.

Changes in expression of c-Fos protein following cocaine-cue extinction learning.

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Nic Dhonnchadha, B Á; Lovascio, B F; Shrestha, N; Lin, A; Leite-Morris, K A; Man, H Y; Kaplan, G B; Kantak, K M

2012-09-01

Extinguishing abnormally strengthened learned responses to cues associated with drugs of abuse remains a key tactic for alleviating addiction. To assist in developing pharmacotherapies to augment exposure therapy for relapse prevention, investigation into neurobiological underpinnings of drug-cue extinction learning is needed. We used regional analyses of c-Fos and GluR2 protein expression to delineate neural activity and plasticity that may be associated with cocaine-cue extinction learning. Rats were trained to self-administer cocaine paired with a light cue, and later underwent a single 2h extinction session for which cocaine was withheld but response-contingent cues were presented (cocaine-cue extinction). Control groups consisted of rats yoked to animals self-administering cocaine and receiving saline non-contingently followed by an extinction session, or rats trained to self-administer cocaine followed by a no-extinction session for which levers were retracted, and cocaine and cues were withheld. Among 11 brain sites examined, extinction training increased c-Fos expression in basolateral amygdala and prelimbic prefrontal cortex of cocaine-cue extinguished rats relative to both control conditions. In dorsal subiculum and infralimbic prefrontal cortex, extinction training increased c-Fos expression in both cocaine-cue and saline-cue extinguished rats relative to the no-extinction control condition. GluR2 protein expression was not altered in any site examined after extinction or control training. Findings suggest that basolateral amygdala and prelimbic prefrontal cortex neurons are activated during acquisition of cocaine-cue extinction learning, a process that is independent of changes in GluR2 abundance. Other sites are implicated in processing the significance of cues that are present early in extinction training. Copyright © 2012 Elsevier B.V. All rights reserved.

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

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- 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

A fear-inducing odor alters PER2 and c-Fos expression in brain regions involved in fear memory.

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Harry Pantazopoulos

Full Text Available Evidence demonstrates that rodents learn to associate a foot shock with time of day, indicating the formation of a fear related time-stamp memory, even in the absence of a functioning SCN. In addition, mice acquire and retain fear memory better during the early day compared to the early night. This type of memory may be regulated by circadian pacemakers outside of the SCN. As a first step in testing the hypothesis that clock genes are involved in the formation of a time-stamp fear memory, we exposed one group of mice to fox feces derived odor (TMT at ZT 0 and one group at ZT 12 for 4 successive days. A separate group with no exposure to TMT was also included as a control. Animals were sacrificed one day after the last exposure to TMT, and PER2 and c-Fos protein were quantified in the SCN, amygdala, hippocampus, and piriform cortex. Exposure to TMT had a strong effect at ZT 0, decreasing PER2 expression at this time point in most regions except the SCN, and reversing the normal rhythm of PER2 expression in the amygdala and piriform cortex. These changes were accompanied by increased c-Fos expression at ZT0. In contrast, exposure to TMT at ZT 12 abolished the rhythm of PER2 expression in the amygdala. In addition, increased c-Fos expression at ZT 12 was only detected in the central nucleus of the amygdala in the TMT12 group. TMT exposure at either time point did not affect PER2 or c-Fos in the SCN, indicating that under a light-dark cycle, the SCN rhythm is stable in the presence of repeated exposure to a fear-inducing stimulus. Taken together, these results indicate that entrainment to a fear-inducing stimulus leads to changes in PER2 and c-Fos expression that are detected 24 hours following the last exposure to TMT, indicating entrainment of endogenous oscillators in these regions. The observed effects on PER2 expression and c-Fos were stronger during the early day than during the early night, possibly to prepare appropriate systems at ZT 0 to

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

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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.

The mesencephalic GCt-ICo complex and tonic immobility in pigeons (Columba livia): a c-Fos study.

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Melleu, Fernando Falkenburger; Lino-de-Oliveira, C; Marino-Neto, J

2017-04-01

Tonic immobility (TI) is a response to a predator attack, or other inescapable danger, characterized by immobility, analgesia and unresponsiveness to external stimuli. In mammals, the periaqueductal gray (PAG) and deep tectal regions control the expression of TI as well as other defensive behaviors. In birds, little is known about the mesencephalic circuitry involved in the control of TI. Here, adult pigeons (both sex, n = 4/group), randomly assigned to non-handled, handled or TI groups, were killed 90 min after manipulations and the brains processed for detection of c-Fos immunoreactive cells (c-Fos-ir, marker for neural activity) in the mesencephalic central gray (GCt) and the adjacent nucleus intercollicularis (ICo). The NADPH-diaphorase staining delineated the boundaries of the sub nuclei in the ICo-GCt complex. Compared to non-handled, TI (but not handling) induced c-Fos-ir in NADPH-diaphorase-rich and -poor regions. After TI, the number of c-Fos-ir increased in the caudal and intermediate areas of the ICo (but not in the GCt), throughout the rostrocaudal axis of the dorsal stratum griseum periventriculare (SGPd) of the optic tectum and in the n. mesencephalicus lateralis pars dorsalis (MLd), which is part of the ascending auditory pathway. These data suggest that inescapable threatening stimuli such as TI may recruit neurons in discrete areas of ICo-GCt complex, deep tectal layer and in ascending auditory circuits that may control the expression of defensive behaviors in pigeons. Additionally, data indicate that the contiguous deep tectal SCPd (but not GCt) in birds may be functionally comparable to the mammalian dorsal PAG.

The transcription factors CREB and c-Fos play key roles in NCAM-mediated neuritogenesis in PC12-E2 cells

DEFF Research Database (Denmark)

Jessen, U; Novitskaya, V; Pedersen, N

2001-01-01

The neural cell adhesion molecule (NCAM) stimulates axonal outgrowth by activation of the Ras-mitogen activated protein kinase (MAPK) pathway and by generation of arachidonic acid. We investigated whether the transcription factors, cyclic-AMP response-element binding protein (CREB) and c-Fos play...... roles in this process by estimating NCAM-dependent neurite outgrowth from PC12-E2 cells grown in co-culture with NCAM-negative or NCAM-positive fibroblasts. PC12-E2 cells were transiently transfected with expression plasmids encoding wild-type or dominant negative forms of CREB and c-Fos or an activated...... form of the MAPK kinase, MEK2. Alternatively, PC12-E2 cells were treated with arachidonic acid, the cAMP analogue dBcAMP, or protein kinase A (PKA) inhibitors. The negative forms of CREB and c-Fos inhibited neurite outgrowth mediated by NCAM, arachidonic acid, dBcAMP, or MEK2. Neither CREB nor c...

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

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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

Integration of growth factor signals at the c-fos serum response element.

Science.gov (United States)

Price, M A; Hill, C; Treisman, R

1996-04-29

A transcription factor ternary complex composed of serum response factor (SRF) and a second factor, ternary complex factor (TCF), mediates the response of the c-fos Serum Response Element to growth factors and mitogens. In NIH3T3 fibroblasts, TCF binding is required for transcriptional activation by the SRE in response to activation of the Ras-Raf-ERK pathway. We compared the properties of three members of the TCF family, Elk-1, SAP-1 and SAP-2 (ERP/NET). Although all the proteins contain sequences required for ternary complex formation with SRF, only Elk-1 and SAP-1 appear to interact with the c-fos SRE efficiently in vivo. Each TCF contains a C-terminal activation domain capable of transcriptional activation in response to activation of the Ras-Raf-ERK pathway, and this is dependent on the integrity of S/T-P motifs conserved between all the TCF family members. In contrast, activation of the SRE by whole serum and the mitogenic phospholipid LPA requires SRF binding alone. Constitutively activated members of the Rho subfamily of Ras-like GTPases are also capable of inducing activation of the SRE in the absence of TCF; unlike activated Ras itself, these proteins do not activate the TCFs in NIH3T3 cells. At the SRE, SRF- and TCF-linked signalling pathways act synergistically to potentiate transcription.

Effects of microRNA-129 and its target gene c-Fos on proliferation and apoptosis of hippocampal neurons in rats with epilepsy via the MAPK signaling pathway.

Science.gov (United States)

Wu, Dong-Mei; Zhang, Yu-Tong; Lu, Jun; Zheng, Yuan-Lin

2018-09-01

This study aims to investigate the effect of microRNA-129 (miR-129) on proliferation and apoptosis of hippocampal neurons in epilepsy rats by targeting c-Fos via the MAPK signaling pathway. Thirty rats were equally classified into a model group (successfully established as chronic epilepsy models) and a normal group. Expression of miR-129, c-Fos, bax, and MAPK was detected by RT-qPCR and Western blotting. Hippocampal neurons were assigned into normal, blank, negative control (NC), miR-129 mimic, miR-129 inhibitor, siRNA-c-Fos, miR-129 inhibitor+siRNA-c-Fos groups. The targeting relationship between miR-129 and c-Fos was predicted and verified by bioinformatics websites and dual-luciferase reporter gene assay. Cell proliferation after transfection was measured by MTT assay, and cell cycle and apoptosis by flow cytometry. c-Fos is a potential target gene of miR-129. Compared with the normal group, the other six groups showed a decreased miR-129 expression; increased expression of expression of c-Fos, Bax, and MAPK; decreased proliferation; accelerated apoptosis; more cells arrested in the G1 phase; and fewer cells arrested in the S phase. Compared with the blank and NC groups, the miR-129 mimic group and the siRNA-c-Fos group showed decreased expression of c-Fos, Bax, and MAPK, increased cells proliferation, and decreased cell apoptosis, fewer cells arrested in the G1 phase and more cells arrested in the S phase. However, the miR-129 inhibitor groups showed reverse consequences. This study suggests that miR-129 could inhibit the occurrence and development of epilepsy by repressing c-Fos expression through inhibiting the MAPK signaling pathway. © 2017 Wiley Periodicals, Inc.

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

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

International Nuclear Information System (INIS)

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)

Conditioned taste aversion memory and c-Fos induction are disrupted in RIIbeta-protein kinase A mutant mice.

Science.gov (United States)

Koh, Ming Teng; Clarke, Sharon N D A; Spray, Kristina J; Thiele, Todd E; Bernstein, Ilene L

2003-07-14

The cAMP-dependent protein kinase (PKA) signaling pathway has been implicated in many forms of learning. The present studies examined conditioned taste aversion (CTA) learning, an amygdala-dependent task, in mice with a targeted disruption of a gene for a specific regulatory subunit of PKA (RIIbeta), which is selectively expressed in amygdala. Null mutant (RIIbeta(-/-)) mice and littermate controls (RIIbeta(+/+)) were tested for protein synthesis-independent short-term memory (STM) and protein synthesis-dependent long-term memory (LTM) for CTAs. The ability of the unconditioned stimulus (US) drug, LiCl, to induce c-Fos in regions thought to be important in this learning was also determined. RIIbeta(-/-) mice showed significant impairment in CTA memory when tested 24h after training (LTM). In contrast, STM was normal. With regard to the c-Fos response to LiCl, the US drug, significant elevations were evident in brainstem (nucleus of the solitary tract) and pontine (parabrachial nucleus) regions, in mutants as well as wild-type controls. However, in amygdala, elevations were seen in controls but were absent in the mutants. These findings suggest that disruption of PKA signaling interferes with LTM consolidation of CTA and that a possible mediator of this effect is interference with c-Fos expression in amygdala which may be necessary for CTA memory.

PIAS1 Promotes Lymphomagenesis through MYC Upregulation

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Andrea Rabellino

2016-06-01

Full Text Available The MYC proto-oncogene is a transcription factor implicated in a broad range of cancers. MYC is regulated by several post-translational modifications including SUMOylation, but the functional impact of this post-translational modification is still unclear. Here, we report that the SUMO E3 ligase PIAS1 SUMOylates MYC. We demonstrate that PIAS1 promotes, in a SUMOylation-dependent manner, MYC phosphorylation at serine 62 and dephosphorylation at threonine 58. These events reduce the MYC turnover, leading to increased transcriptional activity. Furthermore, we find that MYC is SUMOylated in primary B cell lymphomas and that PIAS1 is required for the viability of MYC-dependent B cell lymphoma cells as well as several cancer cell lines of epithelial origin. Finally, Pias1-null mice display endothelial defects reminiscent of Myc-null mice. Taken together, these results indicate that PIAS1 is a positive regulator of MYC.

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.

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

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.

Systemic L-Kynurenine sulfate administration disrupts object recognition memory, alters open field behavior and decreases c-Fos immunopositivity in C57Bl/6 mice.

Science.gov (United States)

Varga, Dániel; Herédi, Judit; Kánvási, Zita; Ruszka, Marian; Kis, Zsolt; Ono, Etsuro; Iwamori, Naoki; Iwamori, Tokuko; Takakuwa, Hiroki; Vécsei, László; Toldi, József; Gellért, Levente

2015-01-01

L-Kynurenine (L-KYN) is a central metabolite of tryptophan degradation through the kynurenine pathway (KP). The systemic administration of L-KYN sulfate (L-KYNs) leads to a rapid elevation of the neuroactive KP metabolite kynurenic acid (KYNA). An elevated level of KYNA may have multiple effects on the synaptic transmission, resulting in complex behavioral changes, such as hypoactivity or spatial working memory deficits. These results emerged from studies that focused on rats, after low-dose L-KYNs treatment. However, in several studies neuroprotection was achieved through the administration of high-dose L-KYNs. In the present study, our aim was to investigate whether the systemic administration of a high dose of L-KYNs (300 mg/bwkg; i.p.) would produce alterations in behavioral tasks (open field or object recognition) in C57Bl/6j mice. To evaluate the changes in neuronal activity after L-KYNs treatment, in a separate group of animals we estimated c-Fos expression levels in the corresponding subcortical brain areas. The L-KYNs treatment did not affect the general ambulatory activity of C57Bl/6j mice, whereas it altered their moving patterns, elevating the movement velocity and resting time. Additionally, it seemed to increase anxiety-like behavior, as peripheral zone preference of the open field arena emerged and the rearing activity was attenuated. The treatment also completely abolished the formation of object recognition memory and resulted in decreases in the number of c-Fos-immunopositive-cells in the dorsal part of the striatum and in the CA1 pyramidal cell layer of the hippocampus. We conclude that a single exposure to L-KYNs leads to behavioral disturbances, which might be related to the altered basal c-Fos protein expression in C57Bl/6j mice.

Interleukin-4 inhibits RANKL-induced expression of NFATc1 and c-Fos: A possible mechanism for downregulation of osteoclastogenesis

International Nuclear Information System (INIS)

Kamel Mohamed, Saad Gad; Sugiyama, Eiji; Shinoda, Kouichiro; Hounoki, Hiroyuki; Taki, Hirofumi; Maruyama, Muneharu; Miyahara, Tatsuro; Kobayashi, Masashi

2005-01-01

Interleukin-4 (IL-4), an anti-inflammatory cytokine, has been shown to inhibit osteoclast differentiation. Therefore, this cytokine is considered to be a promising therapeutic applicant for bone-resorbing diseases such as rheumatoid arthritis (RA). Recently NFATc1, a transcription factor, has been shown to play critical roles in osteoclastogenesis. The aim of this study was to clarify the role of IL-4 on the intracellular signaling of NFATc1. A RAW264.7 monocyte/macrophage cell line and murine bone marrow precursors were differentiated into osteoclasts in the presence of receptor activator of nuclear factor κB ligand (RANKL) and/or macrophage colony-stimulating factor. Tartrate-resistant acid phosphatase (TRAP) staining and a pit assay using dentine were used for the identification of activated osteoclasts. The protein expression of IL-4 receptor, NFATc1, and c-Fos was determined by Western blot analysis. In addition, the gene expression of NFATc1 and c-Fos was determined by reverse transcription and polymerase chain reaction. The IL-4 receptor was constitutively expressed in RAW264.7 cells. RANKL induced osteoclast generation, as determined by TRAP staining and pit assay. IL-4 inhibited RANKL-induced osteoclastogenesis at low concentrations of 10 ng/ml and more. Interestingly, IL-4 potently inhibited RANKL-induced expression of NFATc1 at mRNA level. Furthermore, IL-4 inhibited c-Fos expression, which is shown to be responsible for NFATc1 expression, in time- and dose-dependent manners. In addition, IL-4 inhibited the RANKL-induced expression of NFATc1 and c-Fos in murine bone marrow cells. Thus, we suggest that IL-4 may downregulate osteoclastogenesis in part through inhibition of the expression of transcription factors, NFATc1 and c-Fos. These findings provide new insight into development of new medication for osteoporosis and RA

Expression levels of transcription factors c-Fos and c-Jun and transmembrane protein HAb18G/CD147 in urothelial carcinoma of the bladder.

Science.gov (United States)

Huhe, Muren; Liu, Shuangshuang; Zhang, Yang; Zhang, Zheng; Chen, Zhinan

2017-05-01

The aim of the present study was to investigate the prognostic significance of the expression of transcription factors, c-Fos, c-Jun and transmembrane protein CD147, in urothelial carcinoma of the bladder (UCB). The current study investigated the clinical significance of these factors in the development, progression and survival analysis of UCB. Immunohistochemistry was employed to analyze c‑Fos, c‑Jun and CD147 expression in 41 UCB cases and 34 non‑cancerous human bladder tissues. These results were scored in a semi‑quantitative manner based on the intensity and percentage of tumor cells that presented immunoreactivity. Protein levels of CD147, c‑Fos and c‑Jun expression were upregulated in 22 (53.7%), 10 (24.4%) and 9 (22.0%) UCB cases, respectively. High levels of c‑Jun correlated with the AJCC cancer staging manual (7th edition; P=0.038). Univariate analysis revealed that upregulated CD147 (P=0.038) or c‑Jun (P=0.008) was associated with poor overall survival (OS), respectively. Further analysis revealed that either CD147‑c‑Fos‑c‑Jun co‑expression (P=0.004), or CD147‑c‑Jun co‑expression (P=0.037) and c‑Fos‑c‑Jun co‑expression (PCD147, c‑Jun or c‑Fos were independent risk indicators for death in UCB patients. Increased expression of c‑Jun or CD147, as well as co‑expression of CD147‑c‑Jun, c‑Jun‑c‑Fos or CD147‑c‑Jun‑c‑Fos has prognostic significance for UCB patients. Therefore, high CD147 and c‑Jun expression may serve roles in tumor progression and may be diagnostic and therapeutic targets in UCB whether alone or in combination.

Comparison of alterations in c-fos and Egr-1 (zif268) expression throughout the rat brain following acute administration of different classes of antidepressant compounds.

Science.gov (United States)

Slattery, David A; Morrow, John A; Hudson, Alan L; Hill, David R; Nutt, David J; Henry, Brian

2005-07-01

The majority of immediate-early gene (IEG) studies focus on a few key brain regions associated with the class of psychoactive compound being studied. Recently, using a meta-analysis of the c-fos literature, we demonstrated the utility of c-fos profiling to classify such compounds. The present study examined acute delivery of a range of antidepressant classes; fluoxetine, imipramine, LiCl, and mirtazapine. The dual aims were to study the IEG profiles of these varying classes of antidepressants throughout the rat brain and to compare the utility of c-fos or Egr-1 as IEGs to classify clinically efficacious antidepressants. All antidepressants increased c-fos mRNA in the central amygdala, as previously shown, while c-fos was also increased in the anterior insular cortex and significantly decreased within the septum. Although acute antidepressant administration altered c-fos expression in a number of brain regions, Egr-1 expression was only significantly altered in the central amygdala, suggesting that Egr-1 may not be as useful a marker to investigate acute antidepressant treatment. The fact that these drugs, including the previously unclassified antidepressant mirtazapine, share a number of common loci of activation, which are implicated by human and animal studies in depression, adds further support to the use of IEG mapping to classify psychoactive compounds.

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.

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

Comparative study of c-Fos expression in rat dorsal vagal complex and nucleus ambiguus induced by different durations of restraint water-immersion stress.

Science.gov (United States)

Zhang, Yu-Yu; Cao, Guo-Hong; Zhu, Wen-Xing; Cui, Xi-Yun; Ai, Hong-Bin

2009-06-30

Restraint water-immersion stress (RWIS) of rats induces vagally-mediated gastric dysfunction. The present work explored the effects of different durations of RWIS on neuronal activities of the dorsal vagal complex (DVC) and the nucleus ambiguous (NA) in rats. Male Wistar rats were exposed to RWIS for 0, 30, 60, 120, or 180 min. Then, a c-Fos immunoperoxidase technique was utilized to assess neuronal activation. Resumptively, c-Fos expression in DVC and NA peaked at 60 min of stress, subsequently decreased gradually with increasing durations of RWIS. Interestingly, the most intense c-Fos expression was observed in the dorsal motor nucleus of the vagus (DMV) during the stress, followed by NA, nucleus of solitary tract (NTS) and area postrema (AP). The peak of c-Fos expression in caudal DMV appeared at 120 min of the stress, slower than that in rostral and intermediate DMV. The c-Fos expression in intermediate and caudal NTS was significantly more intense than that in rostral NTS. These results indicate that the neuronal hyperactivity of DMV, NA, NTS and AP, the primary center that control gastric functions, especially DMV and NA, may play an important role in the disorders of gastric motility and secretion induced by RWIS.

Protective effect of c-fos antisense oligonucleotides on brain damage induced by glutamate%c-fos反义寡核苷酸对谷氨酸神经毒性鼠脑损伤的防护

Institute of Scientific and Technical Information of China (English)

岳少杰; 陶永光; 罗自强; 冯德云; 伍赶球

2001-01-01

Objective　To investigate the relation between glutamate neurotoxicity and c-fos gene expression. Methods　c-fos antisense oligonucleotides (AS ODN) was injected into the right lateral ventricles of 9 SD rats to block the c-fos gene expression in brain tissue. c-fos sense oligonucleotides （S ODN）was used a control. The numbers and morphology of neurons in both cerebral cortex and hippocampal CA1 were detected by MIAS-300 image analysing instrument. c-fos gene expression in brain was observed by immunohistochemical method. The content of water and electrolytes in the brain tissue and Ca2+ in the synapse were measured. Results　The c-fos AS ODN blocked the c-fos gene expression and reduced the content of both water and sodium in brain tissue and Ca2+ in symptosome, thus alleviating the morphological damage in neuron. S ODN did not have such effect. Conclusion　c-fos gene expression plays an important role in mediating the effect of glutamate neurotoxicity. Blocking the c-fos gene expression could antagonize glutamate neurotoxicity.%目的　探讨c-fos基因的表达在谷氨酸神经毒性中的作用。方法　在9只SD大鼠侧脑室注射c-fos反义寡核苷酸以阻断脑组织c-fos基因的表达，并用c-fos正义寡核苷酸为对照。观察脑组织中水、电解质含量和突触体内Ca2+浓度的变化，并采用细胞形态计量分析及免疫组织化学方法，观察大脑皮质、海马CA1区神经细胞数目、形态的变化及c-fos基因的表达。结果　c-fos反义寡核苷酸可有效地阻断脑组织c-fos基因的表达，降低脑组织c-fos阳性细胞率（9.4%±2.8%和74%±3%，P＜0.01），抑制谷氨酸神经毒性所致的脑组织含水量（79.9%±0.4%和82.3%±0.8%，P＜0.01）、钠（5.05 mg/g干重±0.39 mg/g干重和5.98 mg/g干重±0.50 mg/g干重，P＜0.01）及细胞内Ca2+（176 nmol/L±35 nmol/L和344.12±50.13，P＜0.01）含量的增加，抑制谷氨酸所致大脑皮质（157±10和145±7，P＜0

Influence of radiotherapy on expression of the proliferating cell nuclear antigen (PCNA) and c-fos in human cervical cancer

International Nuclear Information System (INIS)

Shi Mei; Wei Lichun; Sun Chaoyang; Ma Haixin; Guo Yan

2001-01-01

Objective: To investigate changes of proliferating cell nuclear antigen (PCNA) expression in human cervical cancer following irradiation. Methods: Immunohistochemical staining for PCNA was performed in frozen sections of formalin-fixed cervical cancer biopsy tissues. Results: The majority of the cancer cells showed PCNA-immunoreactivity before irradiation. Following irradiation (30-40 Gy/15-20 f) PCNA-immuno-positive staining was hardly detectable in most of the cancer cells. The PCNA-immunoreactivity, however, increased after radiotherapy, and moderate or heavy immuno-positive staining for PCNA was seen in irradiated mesenchymal tissue cells. On the other hand, after irradiation Fos-immunoreactivity decreased remarkably, and Fos-immuno-positive staining was hardly detectable in most of cancer cells. No obvious change in Fos-immuno-reactivity, however, was seen in mesenchymal connective tissue following irradiation. Conclusion: Irradiation inhibits PCNA and c-fos expression in cervical cancer cells whereas it induces the expression of PCNA in mesenchymal tissue cells. The present results suggest that expression of PCNA and c-fos may be regarded as a molecular marker for evaluating the cancer cell proliferation and mesenchymal tissue repair during radiotherapy of human cervical cancer

Interplay among Drosophila transcription factors Ets21c, Fos and Ftz-F1 drives JNK-mediated tumor malignancy

Directory of Open Access Journals (Sweden)

Eva Külshammer

2015-10-01

Full Text Available Cancer initiation and maintenance of the transformed cell state depend on altered cellular signaling and aberrant activities of transcription factors (TFs that drive pathological gene expression in response to cooperating genetic lesions. Deciphering the roles of interacting TFs is therefore central to understanding carcinogenesis and for designing cancer therapies. Here, we use an unbiased genomic approach to define a TF network that triggers an abnormal gene expression program promoting malignancy of clonal tumors, generated in Drosophila imaginal disc epithelium by gain of oncogenic Ras (RasV12 and loss of the tumor suppressor Scribble (scrib1. We show that malignant transformation of the rasV12scrib1 tumors requires TFs of distinct families, namely the bZIP protein Fos, the ETS-domain factor Ets21c and the nuclear receptor Ftz-F1, all acting downstream of Jun-N-terminal kinase (JNK. Depleting any of the three TFs improves viability of tumor-bearing larvae, and this positive effect can be enhanced further by their combined removal. Although both Fos and Ftz-F1 synergistically contribute to rasV12scrib1 tumor invasiveness, only Fos is required for JNK-induced differentiation defects and Matrix metalloprotease (MMP1 upregulation. In contrast, the Fos-dimerizing partner Jun is dispensable for JNK to exert its effects in rasV12scrib1 tumors. Interestingly, Ets21c and Ftz-F1 are transcriptionally induced in these tumors in a JNK- and Fos-dependent manner, thereby demonstrating a hierarchy within the tripartite TF network, with Fos acting as the most upstream JNK effector. Of the three TFs, only Ets21c can efficiently substitute for loss of polarity and cooperate with RasV12 in inducing malignant clones that, like rasV12scrib1 tumors, invade other tissues and overexpress MMP1 and the Drosophila insulin-like peptide 8 (Dilp8. While rasV12ets21c tumors require JNK for invasiveness, the JNK activity is dispensable for their growth. In conclusion, our

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.

Changes in nucleus accumbens and neostriatal c-Fos and DARPP-32 immunoreactivity during different stages of food-reinforced instrumental training.

Science.gov (United States)

Segovia, Kristen N; Correa, Merce; Lennington, Jessica B; Conover, Joanne C; Salamone, John D

2012-04-01

Nucleus accumbens is involved in several aspects of instrumental behavior, motivation and learning. Recent studies showed that dopamine (DA) release in the accumbens shell was significantly increased on the first day of training on a fixed ratio (FR) 5 schedule (i.e. the transition from FR1 to FR5) compared with those rats that continued FR1 training, even though the rats on their first day of FR5 training received less food reinforcement than rats continuing on the FR1 schedule. Additionally, the second day of FR5 responding was marked by a significant increase in DA release in accumbens core. The present studies employed immunohistochemical methods to characterize the changes in cellular markers of accumbens and neostriatal neural activity that occur during various stages of food-reinforced FR5 training. c-Fos and DARPP-32 immunoreactivity in accumbens shell was significantly increased on the first day of FR5 training, while core c-Fos and DARPP-32 expression showed large increases on the second day of FR5 training. Additional studies showed that c-Fos and DARPP-32 expression in neostriatum increased after more extensive training. Double-labeling studies with immunofluorescence methods indicated that increases in accumbens c-Fos and DARPP-32 expression were primarily seen in substance-P-positive neurons. These increases in accumbens c-Fos and DARPP-32 immunoreactivity seen during the initial phases of FR training may reflect several factors, including novelty, learning, stress or the presentation of a work-related challenge to the organism. Moreover, it appears that the separate subregions of the striatal complex are differentially activated at distinct phases of instrumental training. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

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

Topical dura mater application of CFA induces enhanced expression of c-fos and glutamate in rat trigeminal nucleus caudalis

DEFF Research Database (Denmark)

Lukács, M; Warfvinge, K; Tajti, J

2017-01-01

BACKGROUND: Migraine is a debilitating neurological disorder where trigeminovascular activation plays a key role. We have previously reported that local application of Complete Freund's Adjuvant (CFA) onto the dura mater caused activation in rat trigeminal ganglion (TG) which was abolished......) was achieved by application of CFA onto the dural parietal surface. SZR72 was given intraperitoneally (i.p.), one dose prior CFA deposition and repeatedly daily for 7 days. Immunohistochemical studies were performed for mapping glutamate, c-fos, PACAP, substance P, IL-6, IL-1β and TNFα in the TNC/Sp5 and other...... regions of the brainstem and at the C1-C2 regions of the spinal cord. RESULTS: We found that CFA increased c-fos and glutamate immunoreactivity in TNC and C1-C2 neurons. This effect was mitigated by SZR72. PACAP positive fibers were detected in the fasciculus cuneatus and gracilis. Substance P, TNFα, IL-6...

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

A role for the immediate early gene product c-fos in imprinting T cells with short-term memory for signal summation.

Directory of Open Access Journals (Sweden)

Carolyn E Clark

Full Text Available T cells often make sequential contacts with multiple DCs in the lymph nodes and are likely to be equipped with mechanisms that allow them to sum up the successive signals received. We found that a period of stimulation as short as two hours could imprint on a T cell a "biochemical memory" of that activation signal that persisted for several hours. This was evidenced by more rapid induction of activation markers and earlier commitment to proliferation upon subsequent stimulation, even when that secondary stimulation occurred hours later. Upregulation of the immediate early gene product c-fos, a component of the AP-1 transcription factor, was maximal by 1-2 hours of stimulation, and protein levels remained elevated for several hours after stimulus withdrawal. Moreover, phosphorylated forms of c-fos that are stable and transcriptionally active persisted for a least a day. Upon brief antigenic stimulation in vivo, we also observed a rapid upregulation of c-fos that could be boosted by subsequent stimulation. Accumulation of phosphorylated c-fos may therefore serve as a biochemical fingerprint of previous suboptimal stimulation, leaving the T cell poised to rapidly resume its activation program upon its next encounter with an antigen-bearing DC.

The mGlu2/3 Receptor Agonists LY354740 and LY379268 Differentially Regulate Restraint-Stress-Induced Expression of c-Fos in Rat Cerebral Cortex

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M. M. Menezes

2013-01-01

Full Text Available Metabotropic glutamate 2/3 (mGlu2/3 receptors have emerged as potential therapeutic targets due to the ability of mGlu2/3 receptor agonists to modulate excitatory transmission at specific synapses. LY354740 and LY379268 are selective and potent mGlu2/3 receptor agonists that show both anxiolytic- and antipsychotic-like effects in animal models. We compared the efficacy of LY354740 and LY379268 in attenuating restraint-stress-induced expression of the immediate early gene c-Fos in the rat prelimbic (PrL and infralimbic (IL cortex. LY354740 (10 and 30 mg/kg, i.p. showed statistically significant and dose-related attenuation of stress-induced increase in c-Fos expression, in the rat cortex. By contrast, LY379268 had no effect on restraint-stress-induced c-Fos upregulation (0.3–10 mg/kg, i.p.. Because both compounds inhibit serotonin 2A receptor (5-HT2AR-induced c-Fos expression, we hypothesize that LY354740 and LY379268 have different in vivo properties and that 5-HT2AR activation and restraint stress induce c-Fos through distinct mechanisms.

Cilostazol induces C-fos expression in the trigeminal nucleus caudalis and behavioural changes suggestive of headache with the migraine-like feature photophobia in female rats

DEFF Research Database (Denmark)

Christensen, S L; Petersen, Steffen; Sørensen, Dorte B

2018-01-01

-like behaviours and c-fos expression in rats. In order to evaluate the predictive validity of the model, we examined the response to the migraine specific drug sumatriptan. Methods The effect of cilostazol (125 mg/kg p.o.) in female Sprague Dawley rats was evaluated on a range of spontaneous behavioural...... parameters, light sensitivity and mechanical sensitivity thresholds. We also measured c-fos expression in the trigeminal nucleus caudalis. Results Cilostazol increased light sensitivity and grooming behaviour. These manifestations were not inhibited by sumatriptan. Cilostazol also induced c-fos expression...... in the trigeminal nucleus caudalis. Furthermore, trigeminal - but not hind paw hyperalgesia was observed. Conclusion The altered behaviours are suggestive of cilostazol induced headache with migraine-like features, but not specific. The presence of head specific hyperalgesia and the c-fos response in the trigeminal...

An indirect action contributes to c-fos induction in paraventricular hypothalamic nucleus by neuropeptide Y

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Neuropeptide Y (NPY) is a well-established orexigenic peptide and hypothalamic paraventricular nucleus (PVH) is one major brain site that mediates the orexigenic action of NPY. NPY induces abundant expression of C-Fos, an indicator for neuronal activation, in the PVH, which has been used extensively...

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

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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

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

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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.

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

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

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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.

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.

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

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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

Modulation of c-Fos and BDNF Protein Expression in Pentylenetetrazole-Kindled Mice following the Treatment with Novel Antiepileptic Compound HHL-6

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Saima Mahmood Malhi

2014-01-01

Full Text Available Brain-derived neurotrophic factor (BDNF and c-Fos are shown to promote epileptogenesis and are taken as a marker of neuronal activity. The present study investigated the expression of BDNF and c-Fos in mice brain with pentylenetetrazol- (PTZ- induced generalized seizure and evaluated the effect of novel tryptamine derivative HHL-6 on the expression of these two markers. The subconvulsive dose of PTZ (50 mg/kg was administered on alternate days in the experimental groups until the seizure scores 4-5 developed in the PTZ-control group. At the end of each experiment, animals were sacrificed, brain samples were collected and cryosectioned, and immunohistochemical analysis of BDNF and c-Fos protein was performed. Data obtained from two sections per mouse (n=12 animals/group is presented as means ± S.E.M. The test compound HHL-6 demonstrated a potent anticonvulsant activity in the PTZ-induced seizure in mice. Significant reduction in the BDNF (P<0.003 and c-Fos (P<0.01 protein expression was observed in the HHL-6 treated group. Based on these results we suggest that one of the possible mechanisms of HHL-6 to inhibit epileptogenesis might be due to its controlling effect on the cellular and molecular expression of the factors that contribute to the development of epileptogenic plasticity in the CNS.

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

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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.

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

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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.

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.

Post-sensitization treatment with rimonabant blocks the expression of cocaine-induced behavioral sensitization and c-Fos protein in mice.

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Marinho, Eduardo A V; Oliveira-Lima, Alexandre J; Yokoyama, Thais S; Santos-Baldaia, Renan; Ribeiro, Luciana T C; Baldaia, Marilia A; da Silva, Raphael Wuo; Hollais, Andre Willian; Talhati, Fernanda; Longo, Beatriz Monteiro; Berro, Lais Fernanda; Frussa-Filho, Roberto

2017-05-01

CB1 receptor antagonists have been shown to prevent acute and long-term behavioral effects of cocaine. Here we evaluate the effectiveness of the CB1 receptor antagonist rimonabant to modify sensitized responses to cocaine. Mice were treated with saline or cocaine injections in a 15-day intermittent sensitization treatment and subsequently treated with either vehicle, 1 or 10mg/kg rimonabant in the drug-associated environment for 8 consecutive days. Animals were then challenged with saline and cocaine in the open-field apparatus on subsequent days to evaluate the expression of conditioned and sensitized effects to cocaine. c-Fos protein expression was evaluated in the nucleus accumbens (NAcc), ventral tegmental area (VTA), basolateral amygdala (BLA), medial prefrontal cortex (mPFC) and caudate-putamen (CPu) after the last (cocaine) challenge. Previous treatment with 10mg/kg rimonabant blocked the expression of conditioned hyperlocomotion and behavioral sensitization to cocaine, but not acute cocaine-induced hyperlocomotion. These behavioral effects were accompanied by significant changes in c-Fos expression in the brain reward system. Chronic cocaine sensitization blunted a subsequent acute cocaine-induced increase in c-Fos protein in the NAcc, effect that was reversed by previous treatment with rimonabant. Treatment with 10mg/kg rimonabant also attenuated the significant increase in c-Fos expression in the CPu, mPFC and BLA induced by previous chronic sensitization with cocaine. Our findings add to the evidence that drugs targeting CB1 receptors are good candidates for the treatment of cocaine abuse and provide further insights into the mechanisms underlying endocannabinoid signaling within the brain reward system in the context of cocaine abuse. Copyright © 2017 Elsevier Inc. All rights reserved.

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...

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.

[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

c-Fos expression in the paternal mouse brain induced by communicative interaction with maternal mates.

Science.gov (United States)

Zhong, Jing; Liang, Mingkun; Akther, Shirin; Higashida, Chiharu; Tsuji, Takahiro; Higashida, Haruhiro

2014-09-11

Appropriate parental care by fathers greatly facilitates health in human family life. Much less is known from animal studies regarding the factors and neural circuitry that affect paternal behavior compared with those affecting maternal behavior. We recently reported that ICR mouse sires displayed maternal-like retrieval behavior when they were separated from pups and caged with their mates (co-housing) because the sires receive communicative interactions via ultrasonic and pheromone signals from the dams. We investigated the brain structures involved in regulating this activity by quantifying c-Fos-immunoreactive cells as neuronal activation markers in the neural pathway of male parental behavior. c-Fos expression in the medial preoptic area (mPOA) was significantly higher in sires that exhibited retrieval behavior (retrievers) than those with no such behavior (non-retrievers). Identical increased expression was found in the mPOA region in the retrievers stimulated by ultrasonic vocalizations or pheromones from their mates. Such increases in expression were not observed in the ventral tegmental area (VTA), nucleus accumbens (NAcc) or ventral palladium (VP). On the following day that we identified the families of the retrievers or non-retrievers, c-Fos expression in neuronal subsets in the mPOA, VTA, NAcc and VP was much higher in the retriever sires when they isolated together with their mates in new cages. This difference was not observed in the singly isolated retriever sires in new cages. The non-retriever sires did not display expression changes in the four brain regions that were assessed. The mPOA neurons appeared to be activated by direct communicative interactions with mate dams, including ultrasonic vocalizations and pheromones. The mPOA-VTA-NAcc-VP neural circuit appears to be involved in paternal retrieval behavior.

Exposure to an open-field arena increases c-Fos expression in a distributed anxiety-related system projecting to the basolateral amygdaloid complex

DEFF Research Database (Denmark)

Hale, M.W.; Hay-Schmidt, A.; Mikkelsen, J.D.

2008-01-01

Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of brain structures including the basolateral amygdala. Our previous studies demonstrate that exposure of rats to an open-field in high- and low-light conditions results in a marked...... increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus (BLA) compared with controls. The neural mechanisms underlying the anatomically specific effects of open-field exposure on c-Fos expression in the BLA are not clear, however, it is likely that this reflects activation...... to this region in combination with c-Fos immunostaining to identify cells responding to exposure to an open-field arena in low-light (8-13 lux) conditions (an anxiogenic stimulus in rats). Adult male Wistar rats received a unilateral microinjection of 4% CTb in phosphate-buffered saline into the basolateral...

Identification of a Novel Proto-oncogenic Network in Head and Neck Squamous Cell Carcinoma.

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Georgy, Smitha R; Cangkrama, Michael; Srivastava, Seema; Partridge, Darren; Auden, Alana; Dworkin, Sebastian; McLean, Catriona A; Jane, Stephen M; Darido, Charbel

2015-09-01

The developmental transcription factor Grainyhead-like 3 (GRHL3) plays a critical tumor suppressor role in the mammalian epidermis through direct regulation of PTEN and the PI3K/AKT/mTOR signaling pathway. GRHL3 is highly expressed in all tissues derived from the surface ectoderm, including the oral cavity, raising a question about its potential role in suppression of head and neck squamous cell carcinoma (HNSCC). We explored the tumor suppressor role of Grhl3 in HNSCC using a conditional knockout (Grhl3 (∆/-) /K14Cre (+) ) mouse line (n = 26) exposed to an oral chemical carcinogen. We defined the proto-oncogenic pathway activated in the HNSCC derived from these mice and assessed it in primary human HNSCC samples, normal oral epithelial cell lines carrying shRNA to GRHL3, and human HNSCC cell lines. Data were analyzed with two-sided chi square and Student's t tests. Deletion of Grhl3 in oral epithelium in mice did not perturb PTEN/PI3K/AKT/mTOR signaling, but instead evoked loss of GSK3B expression, resulting in stabilization and accumulation of c-MYC and aggressive HNSCC. This molecular signature was also evident in a subset of primary human HNSCC and HNSCC cell lines. Loss of Gsk3b in mice, independent of Grhl3, predisposed to chemical-induced HNSCC. Restoration of GSK3B expression blocked proliferation of normal oral epithelial cell lines carrying shRNA to GRHL3 (cell no., Day 8: Scramble ctl, 616±21.8 x 10(3) vs GRHL3-kd, 1194±44 X 10(3), P < .001; GRHL3-kd vs GRHL3-kd + GSK3B, 800±98.84 X 10(3), P = .003) and human HNSCC cells. We defined a novel molecular signature in mammalian HNSCC, suggesting new treatment strategies targeting the GRHL3/GSK3B/c-MYC proto-oncogenic network. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

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

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

Science.gov (United States)

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.

c-Fos immunoreactivity in prefrontal, basal ganglia and limbic areas of the rat brain after central and peripheral administration of ethanol and its metabolite acetaldehyde.

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Kristen N. Segovia

2013-05-01

Full Text Available Considerable evidence indicates that the metabolite of ethanol (EtOH, acetaldehyde, is biologically active. Acetaldehyde can be formed from EtOH peripherally mainly by alcohol dehydrogenase, and also centrally by catalase. EtOH and acetaldehyde show differences in their behavioral effects depending upon the route of administration. In terms of their effects on motor activity and motivated behaviors, when administered peripherally acetaldehyde tends to be more potent than EtOH but shows very similar potency administered centrally. Since dopamine (DA rich areas have an important role in regulating both motor activity and motivation, the present studies were undertaken to compare the effects of central (intraventricular, ICV and peripheral (intraperitoneal, IP administration of EtOH and acetaldehyde on a cellular marker of brain activity, c-Fos immunoreactivity, in DA innervated areas. Male Sprague-Dawley rats received an IP injection of vehicle, EtOH (0.5 or 2.5 g/kg or acetaldehyde (0.1 or 0.5 g/kg or an ICV injection of vehicle, EtOH or acetaldehyde (2.8 or 14.0 µmoles. IP administration of EtOH minimally induced c-Fos in some regions of the prefrontal cortex and basal ganglia, mainly at the low dose (0.5 g/kg, while IP acetaldehyde induced c-Fos in virtually all the structures studied at both doses. Acetaldehyde administered centrally increased c-Fos in all areas studied, a pattern that was very similar to EtOH. Thus, IP administered acetaldehyde was more efficacious than EtOH at inducing c-Fos expression. However, the general pattern of c-Fos induction promoted by ICV EtOH and acetaldehyde was similar. These results are consistent with the pattern observed in behavioral studies in which both substances produced the same magnitude of effect when injected centrally, and produced differences in potency after peripheral administration.

Expression of c-Fos in the rat retrosplenial cortex during instrumental re-learning of appetitive bar-pressing depends on the number of stages of previous training

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Svarnik, Olga E.; Bulava, Alexandra I.; Alexandrov, Yuri I.

2013-01-01

Learning is known to be accompanied by induction of c-Fos expression in cortical neurons. However, not all neurons are involved in this process. What the c-Fos expression pattern depends on is still unknown. In the present work we studied whether and to what degree previous animal experience about Task 1 (the first phase of an instrumental learning) influenced neuronal c-Fos expression in the retrosplenial cortex during acquisition of Task 2 (the second phase of an instrumental learning). Animals were progressively shaped across days to bar-press for food at the left side of the experimental chamber (Task 1). This appetitive bar-pressing behavior was shaped by nine stages (“9 stages” group), five stages (“5 stages” group) or one intermediate stage (“1 stage” group). After all animals acquired the first skill and practiced it for five days, the bar and feeder on the left, familiar side of the chamber were inactivated, and the animals were allowed to learn a similar instrumental task at the opposite side of the chamber using another pair of a bar and a feeder (Task 2). The highest number of c-Fos positive neurons was found in the retrosplenial cortex of “1 stage” animals as compared to the other groups. The number of c-Fos positive neurons in “5 stages” group animals was significantly lower than in “1 stage” animals and significantly higher than in “9 stages” animals. The number of c-Fos positive neurons in the cortex of “9 stages” animals was significantly higher than in home caged control animals. At the same time, there were no significant differences between groups in such behavioral variables as the number of entrees into the feeder or bar zones during Task 2 learning. Our results suggest that c-Fos expression in the retrosplenial cortex during Task 2 acquisition was influenced by the previous learning history. PMID:23847484

The orexin-1 receptor antagonist SB-334867 decreases anxiety-like behavior and c-Fos expression in the hypothalamus of rats exposed to cat odor.

Science.gov (United States)

Vanderhaven, M W; Cornish, J L; Staples, L G

2015-02-01

Increasing evidence suggests that the orexin system is involved in modulating anxiety, and we have recently shown that cat odor-induced anxiety in rats is attenuated by the orexin receptor antagonist SB-334867. In the current experiment, c-Fos expression was used to map changes in neuronal activation following SB-334867 administration in the cat odor anxiety model. Male Wistar rats were exposed to cat odor with or without SB-334867 pre-treatment (10 mg/kg, i.p.). A naïve control group not exposed to cat odor was also used. Following cat odor exposure, brains were processed for c-Fos expression. Vehicle-treated rats showed an increase in anxiety-like behaviors (increased hiding and decreased approach toward the cat odor), and increased c-Fos expression in the posteroventral medial amygdala (MePV), paraventricular hypothalamus (PVN) and dorsal premammillary nucleus (PMd). In rats pretreated with SB-334867, approach scores increased and c-Fos expression decreased in the PVN and PMd. These results provide both behavioral and neuroanatomical evidence for the attenuation of cat odor-induced anxiety in rats via the orexin system. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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.

CGRP infusion in unanesthetized rats increases expression of c-Fos in the nucleus tractus solitarius and caudal ventrolateral medulla, but not in the trigeminal nucleus caudalis

DEFF Research Database (Denmark)

Bhatt, Deepak K; Ramachandran, Roshni; Christensen, Sarah Louise Tangsgaard

2015-01-01

caudalis (TNC) was isolated at different time points after CGRP infusion. The level of c-Fos mRNA and protein expression in TNC were analyzed by qPCR and immunohistochemistry. c-Fos-stained nuclei were also counted in the nucleus tractus solitarius (NTS) and caudal ventrolateral medulla (CVLM), integrative...

c-Fos expression in the supraoptic nucleus is the most intense during different durations of restraint water-immersion stress in the rat.

Science.gov (United States)

Zhang, Yu-Yu; Zhu, Wen-Xing; Cao, Guo-Hong; Cui, Xi-Yun; Ai, Hong-Bin

2009-09-01

Restraint water-immersion stress (RWIS) can induce anxiety, hypothermia, and severe vagally-mediated gastric dysfunction. The present work explored the effects of different durations of RWIS on neuronal activities of the forebrain by c-Fos expression in conscious rats exposed to RWIS for 0, 30, 60, 120, or 180 min. The peak of c-Fos induction was distinct for different forebrain regions. The most intense c-Fos induction was always observed in the supraoptic nucleus (SON), and then in the hypothalamic paraventricular nucleus (PVN), posterior cortical amygdaloid nucleus (PCoA), central amygdaloid nucleus (CeA), and medial prefrontal cortex (mPFC). Moreover, body temperature was reduced to the lowest degree after 60 min of RWIS, and the gastric lesions tended to gradually worsen with the prolonging of RWIS duration. These data strongly suggest that these nuclei participate in the organismal response to RWIS to different degrees, and may be involved in the hypothermia and gastric lesions induced by RWIS.

N-Myc Differentially Regulates Expression of MXI1 Isoforms in Neuroblastoma

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Michael B. Armstrong

2013-12-01

Full Text Available Amplification of the MYCN proto-oncogene is associated with a poor prognosis in patients with metastatic neuroblastoma (NB. MYCN encodes the N-Myc protein, a transcriptional regulator that dimerizes with the Max transcription factor, binds to E-box DNA sequences, and regulates genes involved in cell growth and apoptosis. Overexpression of N-Myc leads to transcriptional activation and an increase in NB cell proliferation. Mxi1, a member of the Myc family of transcriptional regulators, also binds to Max. However, Mxi1 is a transcriptional repressor and inhibits proliferation of NB cells, suggesting that Mxi1 functions as an N-Myc antagonist. Our laboratory previously identified Mxi1-0, an alternatively transcribed Mxi1 isoform. Mxi1-0 has properties distinct from those of Mxi1; in contrast to Mxi1, Mxi1-0 is unable to suppress c-Myc-dependent transcription. We now show that Mxi1-0 expression increases in response to MYCN overexpression in NB cells, with a positive correlation between MYCN and MXI1-0 RNA levels. We also show that N-Myc expression differentially regulates the MXI1 and MXI1-0 promoters: Increased MYCN expression suppresses MXI1 promoter activity while enhancing transcription through the MXI1-0 promoter. Finally, induction of Mxi1-0 leads to increased proliferation, whereas expression of Mxi1 inhibits cell growth, indicating differential roles for these two proteins. These data suggest that N-Myc differentially regulates the expression of MXI1 and MXI1-0 and can alter the balance between the two transcription factors. Furthermore, MXI1-0 appears to be a downstream target of MYCN-dependent signaling pathways and may contribute to N-Myc-dependent cell growth and proliferation.

Comparison between C-FOS Expression in Male and Female Mice During Morphine Withdrawal in the Presence and Absence of Acute Administration of Matricaria Recutita

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Kesmati Mahnaz

2009-06-01

Full Text Available Background: There are some evidences that indicate there are sexual differences in drug abuse and response to synthetic and herbal drugs. It has been shown that the expression of C-FOS increases in many areas of brain during morphine withdrawal. Concerning the sedative effect of Matricaria recutita extract, the aim of this study was to compare expression of C-FOS transcription factor during morphine withdrawal with and without acute administration of Matricaria recutita on male and female adult mice.Materials and Methods: This study was done at Shahid Chamran University of Ahvaz in 2007 on NMRI mice. Male and female mice were assigned into 8 groups (morphine + saline; morphine + naloxone; morphine + Matricaria recutita + naloxone; and morphine + saline + naloxone. To develop morphine dependency, increasing doses of morphine (20, 40, 80 mg/kg injected subcutaneously for 4 days. Mice received a final morphine injection (40 mg/kg 3hours prior to naloxone (5 mg/kg on the day of testing (day 4. Matricaria recutita extract whit a dose of 30 mg/kg was administered intraperitoneally 5 minutes before naloxone injection. In cellular study, 90minute after naloxone injection, mice were decapitated and their brains were separated, then mRNA was extracted from brain tissue. Using DIG-labeled DNA probe of C-FOS, beta-actin and dot blot technique, expression of C-FOS was analyzed by Zero Dscan software. Statistical evaluation of data was performed using student t-test and ANOVA with one factor followed by Duncan test in SPSS software. P values less than 0.05 were considered significant. Results: The rate of expression of C-FOS increased in male mice but decreased significantly in female mice after naloxone-precipitated abstinence P<0.01(. Matricaria recutita attenuated the rate of expression of C-FOS in male mice but it showed synergistic effect on it in female mice P<0.05(.Conclusion: It seems that the cellular processes involving morphine dependency and

Esculetin attenuates receptor activator of nuclear factor kappa-B ligand-mediated osteoclast differentiation through c-Fos/nuclear factor of activated T-cells c1 signaling pathway

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Baek, Jong Min; Park, Sun-Hyang; Cheon, Yoon-Hee; Ahn, Sung-Jun [Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Lee, Myeung Su [Division of Rheumatology, Department of Internal Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Oh, Jaemin, E-mail: jmoh@wku.ac.kr [Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Kim, Ju-Young, E-mail: kimjy1014@gmail.com [Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of)

2015-05-29

Esculetin exerts various biological effects on anti-oxidation, anti-tumors, and anti-inflammation. However, the involvement of esculetin in the bone metabolism process, particularly osteoclast differentiation has not yet been investigated. In the present study, we first confirmed the inhibitory effect of esculetin on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation. We then revealed the relationship between esculetin and the expression of osteoclast-specific molecules to elucidate its underlying mechanisms. Esculetin interfered with the expression of c-Fos and nuclear factor of activated T cell c1 (NFATc1) both at the mRNA and protein level with no involvement in osteoclast-associated early signaling pathways, suppressing the expression of various transcription factors exclusively expressed in osteoclasts such as tartrate-resistant acid phosphatase (Trap), osteoclast-associated receptor (Oscar), dendritic cell-specific transmembrane protein (Dcstamp), osteoclast stimulatory transmembrane protein (Ocstamp), cathepsin K, αvβ3 integrin, and calcitonin receptor (Ctr). Additionally, esculetin inhibited the formation of filamentous actin (F-actin) ring-positive osteoclasts during osteoclast differentiation. However, the development of F-actin structures and subsequent bone resorbing activity of mature osteoclasts, which are observed in osteoclast/osteoblast co-culture systems were not affected by esculetin. Taken together, our results indicate for the first time that esculetin inhibits RANKL-mediated osteoclastogenesis via direct suppression of c-Fos and NFATc1 expression and exerts an inhibitory effect on actin ring formation during osteoclastogenesis. - Highlights: • We first investigated the effects of esculetin on osteoclast differentiation and function. • Our data demonstrate for the first time that esculetin can suppress osteoclastogenesis in vitro. • Esculetin acts as an inhibitor of c-Fos and NFATc1 activation. �

Expression of c-Fos in rat auditory and limbic systems following 22-kHz calls.

Czech Academy of Sciences Publication Activity Database

Ouda, Ladislav; Jílek, Milan; Syka, Josef

2016-01-01

Roč. 308, jul (2016), s. 196-204 ISSN 0166-4328 R&D Projects: GA ČR(CZ) GCP303/11/J005; GA ČR(CZ) GAP303/12/1347; GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:68378041 Keywords : artificial * C-fos expression * hearing * ultrasonic vocalization (USV) Subject RIV: FH - Neurology Impact factor: 3.002, year: 2016

Akv murine leukemia virus enhances bone tumorigenesis in hMT-c-fos-LTR transgenic mice

DEFF Research Database (Denmark)

Schmidt, Jörg; Krump-Konvalinkova, Vera; Luz, Arne

1995-01-01

hMt-c-fos-LTR transgenic mice (U. Rüther, D. Komitowski, F. R. Schubert, and E. F. Wagner. Oncogene 4, 861–865, 1989) developed bone sarcomas in 20% (3/15) of females at 448 ± 25 days and in 8% (1/12) of males at 523 days. After infection of newborns with Akv, an infectious retrovirus derived from...

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

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),

Influence of Pre-Training Predator Stress on the Expression of c-fos mRNA in the Hippocampus, Amygdala, and Striatum Following Long-Term Spatial Memory Retrieval.

Science.gov (United States)

Vanelzakker, Michael B; Zoladz, Phillip R; Thompson, Vanessa M; Park, Collin R; Halonen, Joshua D; Spencer, Robert L; Diamond, David M

2011-01-01

We have studied the influence of pre-training psychological stress on the expression of c-fos mRNA following long-term spatial memory retrieval. Rats were trained to learn the location of a hidden escape platform in the radial-arm water maze, and then their memory for the platform location was assessed 24 h later. Rat brains were extracted 30 min after the 24-h memory test trial for analysis of c-fos mRNA. Four groups were tested: (1) Rats given standard training (Standard); (2) Rats given cat exposure (Predator Stress) 30 min prior to training (Pre-Training Stress); (3) Rats given water exposure only (Water Yoked); and (4) Rats given no water exposure (Home Cage). The Standard trained group exhibited excellent 24 h memory which was accompanied by increased c-fos mRNA in the dorsal hippocampus and basolateral amygdala (BLA). The Water Yoked group exhibited no increase in c-fos mRNA in any brain region. Rats in the Pre-Training Stress group were classified into two subgroups: good and bad memory performers. Neither of the two Pre-Training Stress subgroups exhibited a significant change in c-fos mRNA expression in the dorsal hippocampus or BLA. Instead, stressed rats with good memory exhibited significantly greater c-fos mRNA expression in the dorsolateral striatum (DLS) compared to stressed rats with bad memory. This finding suggests that stressed rats with good memory used their DLS to generate a non-spatial (cue-based) strategy to learn and subsequently retrieve the memory of the platform location. Collectively, these findings provide evidence at a molecular level for the involvement of the hippocampus and BLA in the retrieval of spatial memory and contribute novel observations on the influence of pre-training stress in activating the DLS in response to long-term memory retrieval.

Influence of Pre-Training Predator Stress on the Expression of c-fos mRNA in the Hippocampus, Amygdala and Striatum Following Long-Term Spatial Memory Retrieval

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Michael B VanElzakker

2011-06-01

Full Text Available We have studied the influence of pre-training psychological stress on the expression of c-fos mRNA following long-term spatial memory retrieval. Rats were trained to learn the location of a hidden escape platform in the radial-arm water maze, and then their memory for the platform location was assessed 24 hr later. Rat brains were extracted 30 min after the 24 hr memory test trial for analysis of c-fos mRNA. Four groups were tested: 1 Rats given standard training (Standard; 2 Rats given cat exposure (Predator Stress 30 min prior to training (Pre-Training Stress; 3 Rats given water exposure only (Water Yoked; and 4 Rats given no water exposure (Home Cage. The Standard trained group exhibited excellent 24 hr memory which was accompanied by increased c-fos mRNA in the dorsal hippocampus and basolateral amygdala (BLA. The Water Yoked group exhibited no increase in c-fos mRNA in any brain region. Rats in the Pre-Training Stress group were classified into two subgroups: good and bad memory performers. Neither of the two Pre-Training Stress subgroups exhibited a significant change in c-fos mRNA expression in the dorsal hippocampus or BLA. Instead, stressed rats with good memory exhibited significantly greater c-fos mRNA expression in the dorsolateral striatum (DLS compared to stressed rats with bad memory. This finding suggests that stressed rats with good memory used their DLS to generate a non-spatial (cue-based strategy to learn and subsequently retrieve the memory of the platform location. Collectively, these findings provide evidence at a molecular level for the involvement of the hippocampus and BLA in the retrieval of spatial memory and contribute novel observations on the influence of pre-training stress in activating the DLS in response to long-term memory retrieval.

Influence of Pre-Training Predator Stress on the Expression of c-fos mRNA in the Hippocampus, Amygdala, and Striatum Following Long-Term Spatial Memory Retrieval

Science.gov (United States)

VanElzakker, Michael B.; Zoladz, Phillip R.; Thompson, Vanessa M.; Park, Collin R.; Halonen, Joshua D.; Spencer, Robert L.; Diamond, David M.

2011-01-01

We have studied the influence of pre-training psychological stress on the expression of c-fos mRNA following long-term spatial memory retrieval. Rats were trained to learn the location of a hidden escape platform in the radial-arm water maze, and then their memory for the platform location was assessed 24 h later. Rat brains were extracted 30 min after the 24-h memory test trial for analysis of c-fos mRNA. Four groups were tested: (1) Rats given standard training (Standard); (2) Rats given cat exposure (Predator Stress) 30 min prior to training (Pre-Training Stress); (3) Rats given water exposure only (Water Yoked); and (4) Rats given no water exposure (Home Cage). The Standard trained group exhibited excellent 24 h memory which was accompanied by increased c-fos mRNA in the dorsal hippocampus and basolateral amygdala (BLA). The Water Yoked group exhibited no increase in c-fos mRNA in any brain region. Rats in the Pre-Training Stress group were classified into two subgroups: good and bad memory performers. Neither of the two Pre-Training Stress subgroups exhibited a significant change in c-fos mRNA expression in the dorsal hippocampus or BLA. Instead, stressed rats with good memory exhibited significantly greater c-fos mRNA expression in the dorsolateral striatum (DLS) compared to stressed rats with bad memory. This finding suggests that stressed rats with good memory used their DLS to generate a non-spatial (cue-based) strategy to learn and subsequently retrieve the memory of the platform location. Collectively, these findings provide evidence at a molecular level for the involvement of the hippocampus and BLA in the retrieval of spatial memory and contribute novel observations on the influence of pre-training stress in activating the DLS in response to long-term memory retrieval. PMID:21738501

Exposure to an open-field arena increases c-Fos expression in a distributed anxiety-related system projecting to the basolateral amygdaloid complex.

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Hale, M W; Hay-Schmidt, A; Mikkelsen, J D; Poulsen, B; Shekhar, A; Lowry, C A

2008-08-26

Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of brain structures including the basolateral amygdala. Our previous studies demonstrate that exposure of rats to an open-field in high- and low-light conditions results in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus (BLA) compared with controls. The neural mechanisms underlying the anatomically specific effects of open-field exposure on c-Fos expression in the BLA are not clear, however, it is likely that this reflects activation of specific afferent input to this region of the amygdala. In order to identify candidate brain regions mediating anxiety-induced activation of the basolateral amygdaloid complex in rats, we used cholera toxin B subunit (CTb) as a retrograde tracer to identify neurons with direct afferent projections to this region in combination with c-Fos immunostaining to identify cells responding to exposure to an open-field arena in low-light (8-13 lux) conditions (an anxiogenic stimulus in rats). Adult male Wistar rats received a unilateral microinjection of 4% CTb in phosphate-buffered saline into the basolateral amygdaloid complex. Rats were housed individually for 11 days after CTb injections and handled (HA) for 2 min each day. On the test day rats were either, 1) exposed to an open-field in low-light conditions (8-13 lux) for 15 min (OF); 2) briefly HA or 3) left undisturbed (control). We report that dual immunohistochemical staining for c-Fos and CTb revealed an increase in the percentage of c-Fos-immunopositive basolateral amygdaloid complex-projecting neurons in open-field-exposed rats compared with HA and control rats in the ipsilateral CA1 region of the ventral hippocampus, subiculum and lateral entorhinal cortex. These data are consistent with the hypothesis that exposure to the open-field arena activates an anxiety-related neuronal system with convergent input to the

Brain pattern of histone H3 phosphorylation after acute amphetamine administration: its relationship to brain c-fos induction is strongly dependent on the particular brain area.

Science.gov (United States)

Rotllant, David; Armario, Antonio

2012-02-01

Recent evidence strongly suggests a critical role of chromatin remodelling in the acute and chronic effects of addictive drugs. We reasoned that Immunohistochemical detection of certain histone modifications may be a more specific tool than induction of immediate early genes (i.e. c-fos) to detect brain areas and neurons that are critical for the action of addictive drugs. Thus, in the present work we studied in adult male rats the effects of a high dose of amphetamine on brain pattern of histone H3 phosphorylation in serine 10 (pH3S(10)) and c-fos expression. We firstly observed that amphetamine-induced an increase in the number of pH3S(10) positive neurons in a restricted number of brain areas, with maximum levels at 30 min after the drug administration that declined at 90 min in most areas. In a second experiment we studied colocalization of pH3S(10) immunoreactivity (pH3S(10)-IR) and c-fos expression. Amphetamine increased c-fos expression in medial prefrontal cortex (mPFC), dorsal striatum, nucleus accumbens (Acb), major Island of Calleja (ICjM), central amygdala (CeA), bed nucleus of stria terminalis lateral dorsal (BSTld) and paraventricular nucleus of the hypothalamus (PVN). Whereas no evidence for increase in pH3S(10) positive neurons was found in the mPFC and the PVN, in the striatum and the Acb basically all pH3S(10) positive neurons showed colocalization with c-fos. In ICjM, CeA and BSTld a notable degree of colocalization was found, but an important number of neurons expressing c-fos were negative for pH3S(10). The present results give support to the hypothesis that amphetamine-induced pH3S(10)-IR showed a more restricted pattern than brain c-fos induction, being this difference strongly dependent on the particular brain area studied. It is likely that those nuclei and neurons showing pH3S(10)-IR are more specifically associated to important effects of the drug, including neural plasticity. This article is part of a Special Issue entitled 'Post

N-Myc Differentially Regulates Expression of MXI1 Isoforms in Neuroblastoma1

Science.gov (United States)

Armstrong, Michael B; Mody, Rajen J; Ellis, D Christian; Hill, Adam B; Erichsen, David A; Wechsler, Daniel S

2013-01-01

Amplification of the MYCN proto-oncogene is associated with a poor prognosis in patients with metastatic neuroblastoma (NB). MYCN encodes the N-Myc protein, a transcriptional regulator that dimerizes with the Max transcription factor, binds to E-box DNA sequences, and regulates genes involved in cell growth and apoptosis. Overexpression of N-Myc leads to transcriptional activation and an increase in NB cell proliferation. Mxi1, a member of the Myc family of transcriptional regulators, also binds to Max. However, Mxi1 is a transcriptional repressor and inhibits proliferation of NB cells, suggesting that Mxi1 functions as an N-Myc antagonist. Our laboratory previously identified Mxi1-0, an alternatively transcribed Mxi1 isoform. Mxi1-0 has properties distinct from those of Mxi1; in contrast to Mxi1, Mxi1-0 is unable to suppress c-Myc-dependent transcription. We now show that Mxi1-0 expression increases in response to MYCN overexpression in NB cells, with a positive correlation between MYCN and MXI1-0 RNA levels. We also show that N-Myc expression differentially regulates the MXI1 and MXI1-0 promoters: Increased MYCN expression suppresses MXI1 promoter activity while enhancing transcription through the MXI1-0 promoter. Finally, induction of Mxi1-0 leads to increased proliferation, whereas expression of Mxi1 inhibits cell growth, indicating differential roles for these two proteins. These data suggest that N-Myc differentially regulates the expression of MXI1 and MXI1-0 and can alter the balance between the two transcription factors. Furthermore, MXI1-0 appears to be a downstream target of MYCN-dependent signaling pathways and may contribute to N-Myc-dependent cell growth and proliferation. PMID:24403858

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

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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...

Unconditioned stimulus pathways to the amygdala: effects of lesions of the posterior intralaminar thalamus on foot-shock-induced c-Fos expression in the subdivisions of the lateral amygdala.

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Lanuza, E; Moncho-Bogani, J; Ledoux, J E

2008-08-26

The lateral nucleus of the amygdala (LA) is a site of convergence for auditory (conditioned stimulus) and foot-shock (unconditioned stimulus) inputs during fear conditioning. The auditory pathways to LA are well characterized, but less is known about the pathways through which foot shock is transmitted. Anatomical tracing and physiological recording studies suggest that the posterior intralaminar thalamic nucleus, which projects to LA, receives both auditory and somatosensory inputs. In the present study we examined the expression of the immediate-early gene c-fos in the LA in rats in response to foot-shock stimulation. We then determined the effects of posterior intralaminar thalamic lesions on foot-shock-induced c-Fos expression in the LA. Foot-shock stimulation led to an increase in the density of c-Fos-positive cells in all LA subnuclei in comparison to controls exposed to the conditioning box but not shocked. However, some differences among the dorsolateral, ventrolateral and ventromedial subnuclei were observed. The ventrolateral subnucleus showed a homogeneous activation throughout its antero-posterior extension. In contrast, only the rostral aspect of the ventromedial subnucleus and the central aspect of the dorsolateral subnucleus showed a significant increment in c-Fos expression. The density of c-Fos-labeled cells in all LA subnuclei was also increased in animals placed in the box in comparison to untreated animals. Unilateral electrolytic lesions of the posterior intralaminar thalamic nucleus and the medial division of the medial geniculate body reduced foot-shock-induced c-Fos activation in the LA ipsilateral to the lesion. The number of c-Fos labeled cells on the lesioned side was reduced to the levels observed in the animals exposed only to the box. These results indicate that the LA is involved in processing information about the foot-shock unconditioned stimulus and receives this kind of somatosensory information from the posterior intralaminar

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...

Blunted behavioral and c Fos responses to acidic fumes in the African naked mole-rat.

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LaVinka, Pamela Colleen; Park, Thomas J

2012-01-01

Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%), and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%), naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO(2).

Blunted behavioral and c Fos responses to acidic fumes in the African naked mole-rat.

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Pamela Colleen LaVinka

Full Text Available Acidosis in the skin triggers activation of pain pathways and behaviors indicative of pain in vertebrates. The exception is the naked mole-rat, the only known vertebrate to show physiological and behavioral insensitivity to acid pain in the skin. The goal of the present study was to determine behavioral and physiological responses of this species to airborne acidic fumes, which would be expected to affect the trigeminal pain pathway in other species. Behaviorally, naked mole-rats did not avoid fumes from moderately high concentrations of acetic acid (10 and 20%, and c Fos labeling showed no increase in activity in the trigeminal nuclei and nucleus tractus solitarius. In contrast, these concentrations triggered behavioral aversion and increased Fos activity in other laboratory rodents. For a very high concentration of acetic acid (50%, naked mole-rats showed significant avoidance behavior and increased Fos labeling in the nucleus tractus solitarius caudal region, which receives vagal chemosensory information. However, there was no increase in trigeminal labeling, and in fact, activity significantly decreased. This pattern is opposite of that associated with another irritant, ammonia fumes, which elicited an increase in trigeminal but not nucleus tractus solitarius Fos labeling, and no behavioral avoidance. Behavioral avoidance of acidic fumes, but no increased labeling in the trigeminal pain nucleus is consistent with the notion of adaptations to blunt acid pain, which would be advantageous for naked mole-rats as they normally live under chronically high levels of acidosis-inducing CO(2.

Impact of hydrodynamic injection and phiC31 integrase on tumor latency in a mouse model of MYC-induced hepatocellular carcinoma.

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Lauren E Woodard

2010-06-01

Full Text Available Hydrodynamic injection is an effective method for DNA delivery in mouse liver and is being translated to larger animals for possible clinical use. Similarly, phiC31 integrase has proven effective in mediating long-term gene therapy in mice when delivered by hydrodynamic injection and is being considered for clinical gene therapy applications. However, chromosomal aberrations have been associated with phiC31 integrase expression in tissue culture, leading to questions about safety.To study whether hydrodynamic delivery alone, or in conjunction with delivery of phiC31 integrase for long-term transgene expression, could facilitate tumor formation, we used a transgenic mouse model in which sustained induction of the human C-MYC oncogene in the liver was followed by hydrodynamic injection. Without injection, mice had a median tumor latency of 154 days. With hydrodynamic injection of saline alone, the median tumor latency was significantly reduced, to 105 days. The median tumor latency was similar, 106 days, when a luciferase donor plasmid and backbone plasmid without integrase were administered. In contrast, when active or inactive phiC31 integrase and donor plasmid were supplied to the mouse liver, the median tumor latency was 153 days, similar to mice receiving no injection.Our data suggest that phiC31 integrase does not facilitate tumor formation in this C-MYC transgenic mouse model. However, in groups lacking phiC31 integrase, hydrodynamic injection appeared to contribute to C-MYC-induced hepatocellular carcinoma in adult mice. Although it remains to be seen to what extent these findings may be extrapolated to catheter-mediated hydrodynamic delivery in larger species, they suggest that caution should be used during translation of hydrodynamic injection to clinical applications.

Stress-induced activation of the immediate early gene Arc (activity-regulated cytoskeleton-associated protein) is restricted to telencephalic areas in the rat brain: relationship to c-fos mRNA.

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Ons, Sheila; Martí, Octavi; Armario, Antonio

2004-06-01

Arc is an effector immediate early gene whose expression is induced in situations of increased neuronal activity. However, there is no report on the influence of stress on Arc expression. Here, we compared the induction of both c-fos and Arc mRNAs in the brain of rats exposed to one of three different stressful situations: novel environment, forced swimming and immobilization. An absent or weak c-fos mRNA signal was observed in control rats, whereas those exposed to one of three stressors showed enhanced c-fos expression in a wide range of brain areas. Constitutive Arc expression was observed in some areas such as cortex, striatum, hippocampus, reticular thalamic nucleus and cerebellar cortex. In response to stressors, a strong induction of Arc was observed, but the pattern was different from that of c-fos. For instance, activation of Arc but not c-fos was observed in the nucleus accumbens after immobilization and in the hippocampus after novel environment. No Arc induction was observed in diencephalic and brainstem areas. The present data show that Arc has a neuroanatomically restricted pattern of induction in the brain after emotional stress. Telencephalic activation suggests that a more intense induction of synaptic plasticity is occurring in this area after exposure to emotional stressors.

Repeated forced swim stress enhances CFA-evoked thermal hyperalgesia and affects the expressions of pCREB and c-Fos in the insular cortex.

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Imbe, H; Kimura, A; Donishi, T; Kaneoke, Y

2014-02-14

Stress affects brain activity and promotes long-term changes in multiple neural systems. Exposure to stressors causes substantial effects on the perception and response to pain. In several animal models, chronic stress produces lasting hyperalgesia. The insular (IC) and anterior cingulate cortices (ACC) are the regions exhibiting most reliable pain-related activity. And the IC and ACC play an important role in pain modulation via the descending pain modulatory system. In the present study we examined the expression of phospho-cAMP response element-binding protein (pCREB) and c-Fos in the IC and ACC after forced swim stress (FS) and complete Freund's adjuvant (CFA) injection to clarify changes in the cerebral cortices that affect the activity of the descending pain modulatory system in the rats with stress-induced hyperalgesia. FS (day 1, 10min; days 2-3, 20min) induced an increase in the expression of pCREB and c-Fos in the anterior IC (AIC). CFA injection into the hindpaw after the FS shows significantly enhanced thermal hyperalgesia and induced a decrease in the expression of c-Fos in the AIC and the posterior IC (PIC). Quantitative image analysis showed that the numbers of c-Fos-immunoreactive neurons in the left AIC and PIC were significantly lower in the FS+CFA group (L AIC, 95.9±6.8; L PIC, 181.9±23.1) than those in the naive group (L AIC, 151.1±19.3, pCFA-induced thermal hyperalgesia through dysfunction of the descending pain modulatory system. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Problem-Solving Test: The Role of a Micro-RNA in the Regulation of "fos" Gene Expression

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Szeberenyi, Jozsef

2009-01-01

The "fos" proto-oncogene codes for a component of the AP1 transcription factor, an important regulator of gene expression and cell proliferation. Dysregulation of AP1 function may lead to the malignant transformation of the cell. The present test describes an experiment in which the role of a micro-RNA (miR-7b) in the regulation of "fos" gene…

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

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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.

Analysis of c-Fos induction in response to social interaction in male and female Fisher 344 rats.

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Perkins, Amy E; Woodruff, Elizabeth R; Chun, Lauren E; Spencer, Robert L; Varlinskaya, Elena; Deak, Terrence

2017-10-01

Sex differences in the expression of social behavior are typically apparent in adolescent and adult rats. While the neurobiology underlying juvenile social play behavior has been well characterized, less is known about discrete brain regions involved in adult responsiveness to a same sex peer. Furthermore, whether adult males and females differ in their responsiveness to a social interaction in terms of neuronal activation indexed via immediate early gene (IEG) expression remains to be determined. Thus, the present study was designed to identify key sites relevant to the processing of sensory stimuli (generally) or social stimuli (specifically) after brief exposure to a same-sex social partner by assessing IEG expression. Four-month-old male and female Fisher (F) 344 rats (N=38; n=5-8/group) were either left undisturbed in their home cage as controls (HCC), exposed to a testing context alone for 30min (CXT), or were placed in the context for 20min and then allowed to socially interact (SI) with a sex-matched conspecific for 10min. Females demonstrated greater levels of social behavior, relative to males. Analysis of c-Fos induction revealed that females exhibited greater c-Fos expression in the prefrontal cortex, regardless of condition. In many brain regions, induction was similar in the CXT and SI groups. However, in the bed nucleus of the stria terminalis (BNST), females exhibited greater c-Fos induction in response to the social interaction relative to their male counterparts, indicating a sex difference in responsivity to social stimuli. Taken together, these data suggest that the BNST is a sexually dimorphic region in terms of activation in response to social stimuli. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of naloxone hydrochloride on c-fos protein expression in brain and plasma beta-endorphin level in rats with diffuse brain injury and secondary brain insult

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Jun-jie JING

2012-09-01

Full Text Available Objective　To observe the changes of c-fos protein expression in brain and beta-endorphin (β-EP level in blood plasma in rats with diffuse brain injury (DBI and secondary brain insult (SBI after intraperitoneal injection of naloxone hydrochloride, and explore the role of c-fos andβ-EP in development of SBI in rats. Methods　Seventy health male SD rats were enrolled in the present study and randomly divided into group A (intraperitoneally injected with 0.9% saline after DBI and SBI model was reproduced, group B (injected intraperitoneally with 1.0mg/kg naloxone hydrochloride after DBI and SBI model was reproduced, and group C (intraperitoneally injected with 1.0mg/kg naloxone hydrochloride after DBI and before SBI model was reproduced. The animals were sacrificed 3, 24 and 48 hours after injury, and the number of c-fos positive cells in brain and content of β-EP in blood plasma were determined by immunohistochemistry and radioimmunoassay respectively, the water content and number of injured neurons in brain tissue were measured by pathomorphological observation of the brain tissue. Results　No significant difference was observed between group B and C for all the detection parameters. In group B and C, the water content in brain tissue at 3h and 24h was found to be decreased, while the number of injured neurons at 24h and 48h increased, number of c-fos positive cells in brain at 3h, 24h and 48h decreased, and content of β-EP in blood plasma at 3h and 24h decreased when compared with group A(P < 0.05. Conclusion　Naloxone hydrochloride could decrease the c-fos expression in brain and β-EP level in blood plasma, alleviate the nerve injury, and protect neural function. The therapeutic effect of naloxone administered either after DBI and SBI or after DBI and before SBI was similar.

Bcl-2, Bax, and c-Fos expression correlates to RPE cell apoptosis induced by UV-light and daunorubicin

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Liang, Y G; Jorgensen, A G; Kaestel, C G

2000-01-01

PURPOSE. The aim of this study was to determine the role of Bcl-2, Bcl-X L, Bax, and c-Fos in regulation of apoptosis, induced by ultraviolet-light A (UV-A) and daunorubicin (DNR), in retinal pigment epithelium (RPE) cells grown on bovine extracellular matrix (ECM)-coated or uncoated plastic dishes....... METHODS. Apoptosis in confluent RPE cells cultured on ECM-coated or uncoated dishes was induced by UV-A or DNR. Apoptosis was detected by 7-amino-actinomycin D labeling followed by flow cytometry and by terminal deoxy-transferase mediated X-dUTP nick end labeling (TUNEL). Cellular expression of Bcl-2, Bcl......-X L, Bax, and c-Fos was determined by the use of antibodies and flow cytometry, Western blot analysis, and immunocytochemical staining. RESULTS. Both UV-A and DNR induce apoptosis in human RPE cells in vitro. Human fetal RPE cells grown on ECM-coated dishes were significantly more resistant to UV...

Gene expression in skin tumors induced in hairless mice by chronic exposure to ultraviolet B irradiation

International Nuclear Information System (INIS)

Sato, Hiromi; Tanaka, Misao; Kobayashi, Shizuko; Suzuki, Junko S.; Ogiso, Manabu; Tohyama, Chiharu

1997-01-01

We investigated the expressions of c-Ha-ras, c-jun, c-fos, c-myc genes and p53 protein in the development of skin tumours induced by chronic exposure to UVB without a photosensitizer using hairless mice. When mice were exposed to UVB at a dose of 2 kJ/m 2 three times a week, increased c-Ha-ras and c-myc transcripts were detected after only 5 weeks of exposure, while no tumour appeared on the exposed skin. The increase in gene expression continued until 25 weeks, when tumours, identified pathologically as mainly squamous cell carcinomas (SCC), developed in the dorsal skin. In these SCC, overexpression of c-fos mRNA was also observed along with the increases in c-Ha-ras and c-myc. A single dose of UVB (2 kJ/m 2 ) applied to the backs of hairless mice transiently induced overexpression of the early event genes c-fos, c-jun and c-myc, but not c-Ha-ras, in the exposed area of skin. Accumulation of p53 protein was determined by Western blotting analysis of immunohistochemistry using monoclonal antibodies PAb 240 or 246, which recognize mutant or wide type, respectively. In the SCC, a mutant p53 protein accumulated in the cytoplasm and nucleus. After single-dose irradiation, the increased wild-type p53 protein was observed in the nuclei of epidermal cells. The present results suggest that overexpression of the c-fos, c-myc and c-Ha-ras genes, and the mutational changes in p53 protein might be associated with skin photocarcinogenesis. Moreover, overexpression of the c-Ha-ras and c-myc genes might be an early event in the development of UVB-induced skin tumors in mice. (author)

A selective inhibition of c-Fos/activator protein-1 as a potential therapeutic target for intervertebral disc degeneration and associated pain.

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Makino, Hiroto; Seki, Shoji; Yahara, Yasuhito; Shiozawa, Shunichi; Aikawa, Yukihiko; Motomura, Hiraku; Nogami, Makiko; Watanabe, Kenta; Sainoh, Takeshi; Ito, Hisakatsu; Tsumaki, Noriyuki; Kawaguchi, Yoshiharu; Yamazaki, Mitsuaki; Kimura, Tomoatsu

2017-12-05

Intervertebral disc (IVD) degeneration is a major cause of low back pain. The transcription factor c-Fos/Activator Protein-1 (AP-1) controls the expression of inflammatory cytokines and matrix metalloproteinases (MMPs) that contribute to the pathogenesis IVD degeneration. We investigated the effects of inhibition of c-Fos/AP-1 on IVD degeneration and associated pain. A selective inhibitor, T-5224, significantly suppressed the interleukin-1β-induced up-regulation of Mmp-3, Mmp-13 and Adamts-5 transcription in human nucleus pulposus cells and in a mouse explant culture model of IVD degeneration. We used a tail disc percutaneous needle puncture method to further assess the effects of oral administration of T-5224 on IVD degeneration. Analysis of disc height, T2-magnetic resonance imaging (MRI) findings, and histology revealed that IVD degeneration was significantly mitigated by T-5224. Further, oral administration of T-5224 ameliorated pain as indicated by the extended tail-flick latency in response to heat stimulation of rats with needle-puncture-induced IVD degeneration. These findings suggest that the inhibition of c-Fos/AP-1 prevents disc degeneration and its associated pain and that T-5224 may serve as a drug for the prevention of IVD degeneration.

Chlorella vulgaris reduces the impact of stress on hypothalamic-pituitary-adrenal axis and brain c-fos expression.

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Souza Queiroz, Julia; Marín Blasco, Ignacio; Gagliano, Humberto; Daviu, Nuria; Gómez Román, Almudena; Belda, Xavier; Carrasco, Javier; Rocha, Michelle C; Palermo Neto, João; Armario, Antonio

2016-03-01

Predominantly emotional stressors activate a wide range of brain areas, as revealed by the expression of immediate early genes, such as c-fos. Chlorella vulgaris (CV) is considered a biological response modifier, as demonstrated by its protective activities against infections, tumors and stress. We evaluated the effect of acute pretreatment with CV on the peripheral and central responses to forced swimming stress in adult male rats. Pretreatment with CV produced a significant reduction of stress-related hypothalamic-pituitary-adrenal activation, demonstrated by decreased corticotrophin releasing factor gene expression in the hypothalamic paraventricular nucleus (PVN) and lower ACTH response. Hyperglycemia induced by the stressor was similarly reduced. This attenuated neuroendocrine response to stress occurred in parallel with a diminished c-fos expression in most evaluated areas, including the PVN. The data presented in this study reinforce the usefulness of CV to diminish the impact of stressors, by reducing the HPA response. Although our results suggest a central effect of CV, further studies are necessary to understand the precise mechanisms underpinning this effect. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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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.

Long-distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region upregulating the allele-specific MYC expression in HeLa cells.

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Shen, Congle; Liu, Yongzhen; Shi, Shu; Zhang, Ruiyang; Zhang, Ting; Xu, Qiang; Zhu, Pengfei; Chen, Xiangmei; Lu, Fengmin

2017-08-01

Human papillomavirus (HPV) infection is the most important risk factor for cervical cancer development. In HeLa cell line, the HPV viral genome is integrated at 8q24 in one allele of chromosome 8. It has been reported that the HPV fragment integrated in HeLa genome can cis-activate the expression of proto-oncogene MYC, which is located at 500 kb downstream of the integrated site. However, the underlying molecular mechanism of this regulation is unknown. A recent study reported that MYC was highly expressed exclusively from the HPV-integrated haplotype, and a long-range chromatin interaction between the integrated HPV fragment and MYC gene has been hypothesized. In this study, we provided the experimental evidences supporting this long-range chromatin interaction in HeLa cells by using Chromosome Conformation Capture (3C) method. We found that the integrated HPV fragment, MYC and 8q24.22 was close to each other and might form a trimer in spatial location. When knocking out the integrated HPV fragment or 8q24.22 region from chromosome 8 by CRISPR/Cas9 system, the expression of MYC reduced dramatically in HeLa cells. Interestingly, decreased expression was only observed in three from eight cell clones, when only one 8q24.22 allele was knocked out. Functionally, HPV knockout caused senescence-associated acidic β-gal activity in HeLa cells. These data indicate a long-distance interaction of the integrated HPV fragment with MYC gene and 8q24.22 region, providing an alternative mechanism relevant to the carcinogenicity of HPV integration. © 2017 The Authors International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.

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

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

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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

c-Fos and Arc/Arg3.1 expression in auditory and visual cortices after hearing loss: Evidence of sensory crossmodal reorganization in adult rats.

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Pernia, M; Estevez, S; Poveda, C; Plaza, I; Carro, J; Juiz, J M; Merchan, M A

2017-08-15

Cross-modal reorganization in the auditory and visual cortices has been reported after hearing and visual deficits mostly during the developmental period, possibly underlying sensory compensation mechanisms. However, there are very few data on the existence or nature and timeline of such reorganization events during sensory deficits in adulthood. In this study, we assessed long-term changes in activity-dependent immediate early genes c-Fos and Arc/Arg3.1 in auditory and neighboring visual cortical areas after bilateral deafness in young adult rats. Specifically, we analyzed qualitatively and quantitatively c-Fos and Arc/Arg3.1 immunoreactivity at 15 and 90 days after cochlea removal. We report extensive, global loss of c-Fos and Arc/Arg3.1 immunoreactive neurons in the auditory cortex 15 days after permanent auditory deprivation in adult rats, which is partly reversed 90 days after deafness. Simultaneously, the number and labeling intensity of c-Fos- and Arc/Arg3.1-immunoreactive neurons progressively increase in neighboring visual cortical areas from 2 weeks after deafness and these changes stabilize three months after inducing the cochlear lesion. These findings support plastic, compensatory, long-term changes in activity in the auditory and visual cortices after auditory deprivation in the adult rats. Further studies may clarify whether those changes result in perceptual potentiation of visual drives on auditory regions of the adult cortex. © 2017 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

Transcutaneous electrical nerve stimulation on Yongquan acupoint reduces CFA-induced thermal hyperalgesia of rats via down-regulation of ERK2 phosphorylation and c-Fos expression.

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Yang, Lin; Yang, Lianxue; Gao, Xiulai

2010-07-01

Activation of extracellular signal-regulated kinase-1/2 (ERK1/2) and its involvement in regulating gene expression in spinal dorsal horn, cortical and subcortical neurons by peripheral noxious stimulation contribute to pain hypersensitivity. Transcutaneous electrical nerve stimulation (TENS) is a treatment used in physiotherapy practice to promote analgesia in acute and chronic inflammatory conditions. In this study, a total number of 114 rats were used for three experiments. Effects of complete Freund's adjuvant (CFA)-induced inflammatory pain hypersensitivity and TENS analgesia on ERK1/2 phosphorylation and c-Fos protein expression were examined by using behavioral test, Western blot, and immunostaining methods. We found that CFA injection caused an area of localized swelling, erythema, hypersensitivity to thermal stimuli, the decreased response time of hind paw licking (HPL), as well as upregulation of c-Fos protein expression and ERK2 phosphorylation in the ipsilateral spinal dorsal horn and the contralateral primary somatosensory area of cortex and the amygdala of rats. TENS on Yongquan acupoint for 20 min produced obvious analgesic effects as demonstrated with increased HPL to thermal stimuli of CFA-treated rats. In addition, TENS application suppressed the CFA-induced ERK2 activation and c-Fos protein expression. These results suggest that down-regulation of ERK2 phosphorylation and c-Fos expression were involved in TENS inhibition on CFA-induced thermal hyperalgesia of rats.

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

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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.

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

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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.

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

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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

Neurotensin type 1 receptor-mediated activation of krox24, c-fos and Elk-1: preventing effect of the neurotensin antagonists SR 48692 and SR 142948.

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Portier, M; Combes, T; Gully, D; Maffrand, J P; Casellas, P

1998-07-31

Stimulation of neurotensin (NT) type 1 receptors (NT1-R) in transfected CHO cells is followed by the activation of mitogen-activated protein kinases and the expression of the early response gene krox24. By making point mutations and internal deletions in the krox24 promoter, we show that proximal serum responsive elements (SRE) are involved in transcriptional activation by NT. In addition, we show that the related early response gene c-fos and the Ets protein Elk-1 are also induced by NT. The involvement of NT1-R in NT-mediated activation of krox24, c-fos and Elk-1 was demonstrated by the preventing effect of the specific antagonists SR 48692 and SR 142948. Finally, we show that the activation of krox24 and Elk-1 on the one hand, and that of c-fos on the other hand, result from independent transduction pathways since the former are pertussis toxin-sensitive whereas the latter is insensitive to pertussis toxin.

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

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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.

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

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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

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

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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.

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

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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.

TRPV1 receptors contribute to mediate paclitaxel-induced c-Fos expression in spinal cord dorsal horn neurons

Czech Academy of Sciences Publication Activity Database

Kalynovska, Nataliia; Adámek, Pavel; Paleček, Jiří

2017-01-01

Roč. 66, č. 3 (2017), s. 549-532 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA15-11138S; GA MŠk(CZ) LH15279; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : c-Fos * paclitaxel * TRPV1 * neuropathy * spinal cord Subject RIV: FH - Neurology OBOR OECD: Neurosciences (including psychophysiology Impact factor: 1.461, year: 2016

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

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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.

Long-term effects of a single exposure to immobilization: a c-fos mRNA study of the response to the homotypic stressor in the rat brain.

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Vallès, Astrid; Martí, Octavi; Armario, Antonio

2006-05-01

A single exposure to a severe emotional stressor such as immobilization in wooden boards (IMO) causes long-term (days to weeks) peripheral and central desensitization of the hypothalamic-pituitary-adrenal (HPA) response to the same (homotypic) stressor. However, the brain areas putatively involved in long-term desensitization are unknown. In the present experiment, adult male rats were subjected to 2 h of IMO and, 1 or 4 weeks later, exposed again to 1 h IMO together with stress-naive rats. C-fos mRNA activation just after IMO and 1 h after the termination of IMO (post-IMO) were evaluated by in situ hybridization. Whereas in most brain areas c-fos mRNA induction caused by the last IMO session was similar in stress-naive (controls) and previously immobilized rats, a few brain areas showed a reduced c-fos mRNA response: ventral lateral septum (LSv), medial amygdala (MeA), parvocellular region of the paraventricular hypothalamic nucleus (pPVN), and locus coeruleus (LC). In contrast, an enhanced expression was observed in the medial division of the bed nucleus stria terminalis (BSTMv). The present work demonstrates that a previous experience with a stressor can induce changes in c-fos mRNA expression in different brain areas in response to the homotypic stressor and suggests that LSv, MeA, and BSTMv may be important for providing signals to lower diencephalic (pPVN) and brainstem (LC) nuclei, which results in a lower physiological response to the homotypic stressor.

Beta-Defensin 2 and 3 Promote Bacterial Clearance of Pseudomonas aeruginosa by Inhibiting Macrophage Autophagy through Downregulation of Early Growth Response Gene-1 and c-FOS

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Yongjian Wu

2018-02-01

Full Text Available Beta-defensins 2 and 3 (BD2 and BD3 are inducible peptides present at the sites of infection, and they are well characterized for their antimicrobial activities and immune-regulatory functions. However, no study has thoroughly investigated their immunomodulatory effects on macrophage-mediated immune responses against Pseudomonas aeruginosa (PA. Here, we use THP-1 and RAW264.7 cell lines and demonstrate that BD2 and BD3 suppressed macrophage autophagy but enhanced the engulfment of PA and Zymosan bioparticles as well as the formation of phagolysosomes, using immunofluorescence staining and confocal microscopy. Plate count assay showed that macrophage-mediated phagocytosis and intracellular killing of PA were promoted by BD2 and BD3. Furthermore, microarray and real-time PCR showed that the expression of two genes, early growth response gene-1 (EGR1 and c-FOS, was attenuated by BD2 and BD3. Western blot revealed that BD2 and BD3 inhibited the expression and nuclear translocation of EGR1 and c-FOS. Knockdown of EGR1 and c-FOS by siRNA transfection suppressed macrophage autophagy before and after PA infection; while overexpression of these two transcription factors enhanced autophagy but reversed the role of BD2 and BD3 on macrophage-mediated PA eradication. Together, these results demonstrate a novel immune defense activity of BD2 and BD3, which promotes clearance of PA by inhibiting macrophage autophagy through downregulation of EGR1 and c-FOS.

Myc suppression of Nfkb2 accelerates lymphomagenesis

International Nuclear Information System (INIS)

Keller, Ulrich; Huber, Jürgen; Nilsson, Jonas A; Fallahi, Mohammad; Hall, Mark A; Peschel, Christian; Cleveland, John L

2010-01-01

Deregulated c-Myc expression is a hallmark of several human cancers where it promotes proliferation and an aggressive tumour phenotype. Myc overexpression is associated with reduced activity of Rel/NF-κB, transcription factors that control the immune response, cell survival, and transformation, and that are frequently altered in cancer. The Rel/NF-κB family member NFKB2 is altered by chromosomal translocations or deletions in lymphoid malignancies and deletion of the C-terminal ankyrin domain of NF-κB2 augments lymphocyte proliferation. Precancerous Eμ-Myc-transgenic B cells, Eμ-Myc lymphomas and human Burkitt lymphoma samples were assessed for Nfkb2 expression. The contribution of Nfkb2 to Myc-driven apoptosis, proliferation, and lymphomagenesis was tested genetically in vivo. Here we report that the Myc oncoprotein suppresses Nfkb2 expression in vitro in primary mouse fibroblasts and B cells, and in vivo in the Eμ-Myc transgenic mouse model of human Burkitt lymphoma (BL). NFKB2 suppression by Myc was also confirmed in primary human BL. Promoter-reporter assays indicate that Myc-mediated suppression of Nfkb2 occurs at the level of transcription. The contribution of Nfkb2 to Myc-driven lymphomagenesis was tested in vivo, where Nfkb2 loss was shown to accelerate lymphoma development in Eμ-Myc transgenic mice, by impairing Myc's apoptotic response. Nfkb2 is suppressed by c-Myc and harnesses Myc-driven lymphomagenesis. These data thus link Myc-driven lymphomagenesis to the non-canonical NF-κB pathway

Topical dura mater application of CFA induces enhanced expression of c-fos and glutamate in rat trigeminal nucleus caudalis: attenuated by KYNA derivate (SZR72).

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Lukács, M; Warfvinge, K; Tajti, J; Fülöp, F; Toldi, J; Vécsei, L; Edvinsson, L

2017-12-01

Migraine is a debilitating neurological disorder where trigeminovascular activation plays a key role. We have previously reported that local application of Complete Freund's Adjuvant (CFA) onto the dura mater caused activation in rat trigeminal ganglion (TG) which was abolished by a systemic administration of kynurenic acid (KYNA) derivate (SZR72). Here, we hypothesize that this activation may extend to the trigeminal complex in the brainstem and is attenuated by treatment with SZR72. Activation in the trigeminal nucleus caudalis (TNC) and the trigeminal tract (Sp5) was achieved by application of CFA onto the dural parietal surface. SZR72 was given intraperitoneally (i.p.), one dose prior CFA deposition and repeatedly daily for 7 days. Immunohistochemical studies were performed for mapping glutamate, c-fos, PACAP, substance P, IL-6, IL-1β and TNFα in the TNC/Sp5 and other regions of the brainstem and at the C 1 -C 2 regions of the spinal cord. We found that CFA increased c-fos and glutamate immunoreactivity in TNC and C 1 -C 2 neurons. This effect was mitigated by SZR72. PACAP positive fibers were detected in the fasciculus cuneatus and gracilis. Substance P, TNFα, IL-6 and IL-1β immunopositivity were detected in fibers of Sp5 and neither of these molecules showed any change in immunoreactivity following CFA administration. This is the first study demonstrating that dural application of CFA increases the expression of c-fos and glutamate in TNC neurons. Treatment with the KYNA analogue prevented this expression.

Reciprocal Patterns of c-Fos Expression in the Medial Prefrontal Cortex and Amygdala after Extinction and Renewal of Conditioned Fear

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Knapska, Ewelina; Maren, Stephen

2009-01-01

After extinction of conditioned fear, memory for the conditioning and extinction experiences becomes context dependent. Fear is suppressed in the extinction context, but renews in other contexts. This study characterizes the neural circuitry underlying the context-dependent retrieval of extinguished fear memories using c-Fos immunohistochemistry.…

Regulation of glucose transport and c-fos and egr-1 expression in cells with mutated or endogenous growth hormone receptors

DEFF Research Database (Denmark)

Gong, T W; Meyer, D J; Liao, J

1998-01-01

To identify mechanisms by which GH receptors (GHR) mediate downstream events representative of growth and metabolic responses to GH, stimulation by GH of c-fos and egr-1 expression and glucose transport activity were examined in Chinese hamster ovary (CHO) cells expressing mutated GHR. In CHO cel...

Odor discrimination learning in the Indian greater short-nosed fruit bat (Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus.

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Mukilan, Murugan; Bogdanowicz, Wieslaw; Marimuthu, Ganapathy; Rajan, Koilmani Emmanuvel

2018-04-19

Activity-dependent expression of immediate-early genes (IEGs) is induced by exposure to odor. The present study was designed to investigate whether there is differential expression of IEGs ( Egr-1 , C-fos ) in the brain region mediating olfactory memory in the Indian greater short-nosed fruit bat Cynopterus sphinx We assumed that differential expression of IEGs in different brain regions may orchestrate a preference odor (PO) and aversive odor (AO) memory in C. sphinx We used preferred (0.8% wt/wt of cinnamon powder) and aversive (0.4% wt/vol of citral) odor substances, with freshly-prepared chopped apple, to assess the behavioural response and induction of IEGs in the olfactory bulb, hippocampus and amygdala. After experiencing PO and AO, the bats initially responded to both, later only engaging in feeding bouts in response to the PO food. The expression pattern of Egr-1 and C-fos in the olfactory bulb, hippocampus and amygdala was similar at different time points (15, 30 and 60 min) following the response to PO, but different for AO. The response to AO elevated the level of C-fos expression within 30 min and reduced it at 60 min in both the olfactory bulb and the hippocampus, as opposed to the continuous increase noted in the amygdala. In addition, we tested whether an epigenetic mechanism entailing protein phosphatase-1 (PP-1) acts on IEG expression. The observed PP-1 expression and the level of unmethylated/methylated promoter revealed that the C-fos expression is possibly controlled by an odor-mediated regulation of PP-1. These results in turn imply that the differential expression of C-fos in the hippocampus and amygdala may contribute to olfactory learning and memory in C. sphinx . © 2018. Published by The Company of Biologists Ltd.

Food for Song: Expression of C-Fos and ZENK in the Zebra Finch Song Nuclei during Food Aversion Learning

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Tokarev, Kirill; Tiunova, Anna

2011-01-01

Background Specialized neural pathways, the song system, are required for acquiring, producing, and perceiving learned avian vocalizations. Birds that do not learn to produce their vocalizations lack telencephalic song system components. It is not known whether the song system forebrain regions are exclusively evolved for song or whether they also process information not related to song that might reflect their ‘evolutionary history’. Methodology/Principal Findings To address this question we monitored the induction of two immediate-early genes (IEGs) c-Fos and ZENK in various regions of the song system in zebra finches (Taeniopygia guttata) in response to an aversive food learning paradigm; this involves the association of a food item with a noxious stimulus that affects the oropharyngeal-esophageal cavity and tongue, causing subsequent avoidance of that food item. The motor response results in beak and head movements but not vocalizations. IEGs have been extensively used to map neuro-molecular correlates of song motor production and auditory processing. As previously reported, neurons in two pallial vocal motor regions, HVC and RA, expressed IEGs after singing. Surprisingly, c-Fos was induced equivalently also after food aversion learning in the absence of singing. The density of c-Fos positive neurons was significantly higher than that of birds in control conditions. This was not the case in two other pallial song nuclei important for vocal plasticity, LMAN and Area X, although singing did induce IEGs in these structures, as reported previously. Conclusions/Significance Our results are consistent with the possibility that some of the song nuclei may participate in non-vocal learning and the populations of neurons involved in the two tasks show partial overlap. These findings underscore the previously advanced notion that the specialized forebrain pre-motor nuclei controlling song evolved from circuits involved in behaviors related to feeding. PMID:21695176

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

[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].

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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

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

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

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.

Depressive-like behavioral alterations and c-fos expression in the dopaminergic brain regions in wag/rij rats with genetic absence epilepsy

NARCIS (Netherlands)

Sarkisova, K.Y.; Midzyanovskaya, I.S.; Kulikov, M.A.; Luijtelaar, E.L.J.M. van; Luijtelaar, E.L.J.M. van; Kuznetsova, G.D.; Coenen, A.M.L.; Chepurnov, S.A.

2004-01-01

A Wistar derived inbred line, the WAG/Rij rats, genetically absence epilepsy prone, and their normal counterparts, outbred Wistar rats, were compared in respect to differences in behavior, in acute and chronic antidepressant imipramine treatment and in the immediate early gene c-fos expression in

CILOSTAZOL INDUCES C-FOS EXPRESSION IN THE TRIGEMINAL NUCLEUS CAUDALIS AND BEHAVIOURAL CHANGES SUGGESTIVE OF HEADACHE WITH MIGRAINE-LIKE MANIFESTATIONS IN RATS

DEFF Research Database (Denmark)

Christensen, S. L. T.; Petersen, S.; Sorensen, D. B.

2016-01-01

in rats. Also, we tested the response to sumatriptan in order to evaluate the predictive properties of the model. Methods: The effect of cilostazol (125 mg/kg p.o.) was evaluated on a range of spontaneous behavioural parameters, light sensitivity and mechanical sensitivity thresholds. To assess headache...... specificity we evaluated the c-fos expression in the trigeminal nucleus caudalis. All experiments were done in female Sprague Dawley rats and the oestrous cycle was included in the analyses. Results: We found that cilostazol increased the light sensitivity and grooming behaviour of the rats and decreased......: The altered behaviours are suggestive of headache with migraine features, but not specific. The c-fos response in the trigeminal nucleus caudalis implies that the rats had pain originating from the head. The lack of response to sumatriptan disqualifies the model as predictive, but confirms the translation...

Proliferative signaling initiated in ACTH receptors

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C.F.P. Lotfi

2000-10-01

Full Text Available This article reviews recent results of studies aiming to elucidate modes of integrating signals initiated in ACTH receptors and FGF2 receptors, within the network system of signal transduction found in Y1 adrenocortical cells. These modes of signal integration should be central to the mechanisms underlying the regulation of the G0->G1->S transition in the adrenal cell cycle. FGF2 elicits a strong mitogenic response in G0/G1-arrested Y1 adrenocortical cells, that includes a rapid and transient activation of extracellular signal-regulated kinases-mitogen-activated protein kinases (ERK-MAPK (2 to 10 min, b transcription activation of c-fos, c-jun and c-myc genes (10 to 30 min, c induction of c-Fos and c-Myc proteins by 1 h and cyclin D1 protein by 5 h, and d onset of DNA synthesis stimulation within 8 h. ACTH, itself a weak mitogen, interacts with FGF2 in a complex manner, blocking the FGF2 mitogenic response during the early and middle G1 phase, keeping ERK-MAPK activation and c-Fos and cyclin D1 induction at maximal levels, but post-transcriptionally inhibiting c-Myc expression. c-Fos and c-Jun proteins are mediators in both the strong and the weak mitogenic responses respectively triggered by FGF2 and ACTH. Induction of c-Fos and stimulation of DNA synthesis by ACTH are independent of PKA and are inhibited by the PKC inhibitor GF109203X. In addition, ACTH is a poor activator of ERK-MAPK, but c-Fos induction and DNA synthesis stimulation by ACTH are strongly inhibited by the inhibitor of MEK1 PD98059.

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

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.

The crucial role of the proto-oncogene c-mos in regulation of oocyte maturation

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Irena Jałocha

2010-12-01

Full Text Available Meiosis arrest before fertilization is a common and unique feature of oogenesis in many animal species. On account of the unclear biological significance of meiosis arrest at various stages and for different durations in different animal species, this process and its regulation are the subject of many scientific studies. Studies on the development of ovarian teratomas proved to be helpful in defining the role of particular genes and biochemical cycles in control of the cell cycle in animals. These benign tumors are a valuable source of information on oocyte maturation. The [i]c-mos[/i] proto-oncogene, which is specifically expressed in female and male germ cells, plays a crucial role in control of meiotic cell division in mammals. Its product – Mos protein kinase – acting through mitogen-activated protein kinases (MAPKs regulates critical cellular functions required for homeostasis and decides about cell survival or apoptosis. The MAPK kinase kinase – MAPK kinase – MAPK (MKKK-MKK-MAPK phosphorelay system, in view of its role in cells, seems to be the ideal target for therapeutic intervention in cancer and other diseases. The recent research on human oocytes suggests that the basic mechanisms regulating various stages of oocyte maturation are similar to those described in animals.

Simultaneous Detection of c-Fos Activation from Mesolimbic and Mesocortical Dopamine Reward Sites Following Naive Sugar and Fat Ingestion in Rats.

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Dela Cruz, Julie A D; Coke, Tricia; Bodnar, Richard J

2016-08-24

This study uses cellular c-fos activation to assess effects of novel ingestion of fat and sugar on brain dopamine (DA) pathways in rats. Intakes of sugars and fats are mediated by their innate attractions as well as learned preferences. Brain dopamine, especially meso-limbic and meso-cortical projections from the ventral tegmental area (VTA), has been implicated in both of these unlearned and learned responses. The concept of distributed brain networks, wherein several sites and transmitter/peptide systems interact, has been proposed to mediate palatable food intake, but there is limited evidence empirically demonstrating such actions. Thus, sugar intake elicits DA release and increases c-fos-like immunoreactivity (FLI) from individual VTA DA projection zones including the nucleus accumbens (NAC), amygdala (AMY) and medial prefrontal cortex (mPFC) as well as the dorsal striatum. Further, central administration of selective DA receptor antagonists into these sites differentially reduce acquisition and expression of conditioned flavor preferences elicited by sugars or fats. One approach by which to determine whether these sites interacted as a distributed brain network in response to sugar or fat intake would be to simultaneous evaluate whether the VTA and its major mesotelencephalic DA projection zones (prelimbic and infralimbic mPFC, core and shell of the NAc, basolateral and central-cortico-medial AMY) as well as the dorsal striatum would display coordinated and simultaneous FLI activation after oral, unconditioned intake of corn oil (3.5%), glucose (8%), fructose (8%) and saccharin (0.2%) solutions. This approach is a successful first step in identifying the feasibility of using cellular c-fos activation simultaneously across relevant brain sites to study reward-related learning in ingestion of palatable food in rodents.

Cellular MYCro economics: Balancing MYC function with MYC expression.

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Levens, David

2013-11-01

The expression levels of the MYC oncoprotein have long been recognized to be associated with the outputs of major cellular processes including proliferation, cell growth, apoptosis, differentiation, and metabolism. Therefore, to understand how MYC operates, it is important to define quantitatively the relationship between MYC input and expression output for its targets as well as the higher-order relationships between the expression levels of subnetwork components and the flow of information and materials through those networks. Two different views of MYC are considered, first as a molecular microeconomic manager orchestrating specific positive and negative responses at individual promoters in collaboration with other transcription and chromatin components, and second, as a macroeconomic czar imposing an overarching rule onto all active genes. In either case, c-myc promoter output requires multiple inputs and exploits diverse mechanisms to tune expression to the appropriate levels relative to the thresholds of expression that separate health and disease.

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

Science.gov (United States)

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.

MYC activation is a hallmark of cancer initiation and maintenance.

Science.gov (United States)

Gabay, Meital; Li, Yulin; Felsher, Dean W

2014-06-02

The MYC proto-oncogene has been implicated in the pathogenesis of most types of human tumors. MYC activation alone in many normal cells is restrained from causing tumorigenesis through multiple genetic and epigenetically controlled checkpoint mechanisms, including proliferative arrest, apoptosis, and cellular senescence. When pathologically activated in a permissive epigenetic and/or genetic context, MYC bypasses these mechanisms, enforcing many of the "hallmark" features of cancer, including relentless tumor growth associated with DNA replication and transcription, cellular proliferation and growth, protein synthesis, and altered cellular metabolism. MYC mandates tumor cell fate, by inducing stemness and blocking cellular senescence and differentiation. Additionally, MYC orchestrates changes in the tumor microenvironment, including the activation of angiogenesis and suppression of the host immune response. Provocatively, brief or even partial suppression of MYC back to its physiological levels of activation can result in the restoration of intrinsic checkpoint mechanisms, resulting in acute and sustained tumor regression, associated with tumor cells undergoing proliferative arrest, differentiation, senescence, and apoptosis, as well as remodeling of the tumor microenvironment, recruitment of an immune response, and shutdown of angiogenesis. Hence, tumors appear to be "addicted" to MYC because of both tumor cell-intrinsic, cell-autonomous and host-dependent, immune cell-dependent mechanisms. Both the trajectory and persistence of many human cancers require sustained MYC activation. Multiscale mathematical modeling may be useful to predict when tumors will be addicted to MYC. MYC is a hallmark molecular feature of both the initiation and maintenance of tumorigenesis. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

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

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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.

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.

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.

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.

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.

20(S)-protopanaxadiol (PPD) alleviates scopolamine-induced memory impairment via regulation of cholinergic and antioxidant systems, and expression of Egr-1, c-Fos and c-Jun in mice.

Science.gov (United States)

Lu, Cong; Dong, Liming; Lv, Jingwei; Wang, Yan; Fan, Bei; Wang, Fengzhong; Liu, Xinmin

2018-01-05

20(S)-protopanaxadiol (PPD) possesses various biological properties, including anti-inflammatory, antitumor and anti-fatigue properties. Recent studies found that PPD functioned as a neurotrophic agent to ameliorate the sensory deficit caused by glutamate-induced excitotoxicity through its antioxidant effects and exhibited strong antidepressant-like effects in vivo. The objective of the present study was first to investigate the effect of PPD in scopolamine (SCOP)-induced memory deficit in mice and the potential mechanisms involved. In this study, mice were pretreated with PPD (20 and 40 μmol/kg) and donepezil (1.6 mg/kg) intraperitoneally (i.p) for 14 days. Then, open field test was used to assess the effect of PPD on the locomotor activity and mice were daily injected with SCOP (0.75 mg/kg) to induce cognitive deficits and then subjected to behavioral tests by object location recognition (OLR) experiment and Morris water maze (MWM) task. The cholinergic system function, oxidative stress biomarkers and protein expression of Egr-1, c-Fos, and c-Jun in mouse hippocampus were examined. PPD was found to significantly improve the performance of amnesia mice in OLR and MWM tests. PPD regulated cholinergic function by inhibiting SCOP-induced elevation of acetylcholinesterase (AChE) activity, decline of choline acetyltransferase (ChAT) activity and decrease of acetylcholine (Ach) level. PPD suppressed oxidative stress by increasing activities of antioxidant enzymes such as superoxide dismutase (SOD) and lowering maleic diadehyde (MDA) level. Additionally, PPD significantly elevated the expression of Egr-1, c-Fos, and c-Jun in hippocampus at protein level. Taken together, all these results suggested that 20(S)-protopanaxadiol (PPD) may be a candidate compound for the prevention against memory loss in some neurodegenerative diseases such as Alzheimer's disease (AD). Copyright © 2017. Published by Elsevier B.V.

Defective double-strand DNA break repair and chromosomal translocations by MYC overexpression.

Science.gov (United States)

Karlsson, Asa; Deb-Basu, Debabrita; Cherry, Athena; Turner, Stephanie; Ford, James; Felsher, Dean W

2003-08-19

DNA repair mechanisms are essential for the maintenance of genomic integrity. Disruption of gene products responsible for DNA repair can result in chromosomal damage. Improperly repaired chromosomal damage can result in the loss of chromosomes or the generation of chromosomal deletions or translocations, which can lead to tumorigenesis. The MYC protooncogene is a transcription factor whose overexpression is frequently associated with human neoplasia. MYC has not been previously implicated in a role in DNA repair. Here we report that the overexpression of MYC disrupts the repair of double-strand DNA breaks, resulting in a several-magnitude increase in chromosomal breaks and translocations. We found that MYC inhibited the repair of gamma irradiation DNA breaks in normal human cells and blocked the repair of a single double-strand break engineered to occur in an immortal cell line. By spectral karyotypic analysis, we found that MYC even within one cell division cycle resulted in a several-magnitude increase in the frequency of chromosomal breaks and translocations in normal human cells. Hence, MYC overexpression may be a previously undescribed example of a dominant mutator that may fuel tumorigenesis by inducing chromosomal damage.

Regulation of the JNK3 signaling pathway during islet isolation: JNK3 and c-fos as new markers of islet quality for transplantation.

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Saida Abdelli

Full Text Available Stress conditions generated throughout pancreatic islet processing initiate the activation of pro-inflammatory pathways and beta-cell destruction. Our goal is to identify relevant and preferably beta-specific markers to assess the activation of beta-cell stress and apoptotic mechanisms, and therefore the general quality of the islet preparation prior to transplantation. Protein expression and activation were analyzed by Western blotting and kinase assays. ATP measurements were performed by a luminescence-based assay. Oxygen consumption rate (OCR was measured based on standard protocols using fiber optic sensors. Total RNA was used for gene expression analyzes. Our results indicate that pancreas digestion initiates a potent stress response in the islets by activating two stress kinases, c-Jun N-terminal Kinase (JNK and p38. JNK1 protein levels remained unchanged between different islet preparations and following culture. In contrast, levels of JNK3 increased after islet culture, but varied markedly, with a subset of preparations bearing low JNK3 expression. The observed changes in JNK3 protein content strongly correlated with OCR measurements as determined by the Spearman's rank correlation coefficient rho [Formula: see text] in the matching islet samples, while inversely correlating with c-fos mRNA expression [Formula: see text]. In conclusion, pancreas digestion recruits JNK and p38 kinases that are known to participate to beta-cell apoptosis. Concomitantly, the islet isolation alters JNK3 and c-fos expression, both strongly correlating with OCR. Thus, a comparative analysis of JNK3 and c-fos expression before and after culture may provide for novel markers to assess islet quality prior to transplantation. JNK3 has the advantage over all other proposed markers to be islet-specific, and thus to provide for a marker independent of non-beta cell contamination.

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.

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...

Ghrelin agonists impact on Fos protein expression in brain areas related to food intake regulation in male C57BL/6 mice

Czech Academy of Sciences Publication Activity Database

Pirnik, Z.; Bundziková, J.; Holubová, Martina; Pýchová, Miroslava; Fehrentz, J. A.; Martinez, J.; Železná, Blanka; Maletínská, Lenka; Kiss, A.

2011-01-01

Roč. 59, č. 6 (2011), s. 889-895 ISSN 0197-0186 R&D Projects: GA ČR GA303/09/0744 Institutional research plan: CEZ:AV0Z40550506 Keywords : ghrelin agonists * Fos immunohistochemistry * male C57BL/6 mice Subject RIV: CC - Organic Chemistry Impact factor: 2.857, year: 2011

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.

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

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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.

Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

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Sonego, Andreza B; Gomes, Felipe V; Del Bel, Elaine A; Guimaraes, Francisco S

2016-08-01

Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant. Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic. In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol. To further investigate this latter effect, we tested whether CBD (15-60mg/kg) would attenuate the catalepsy and c-Fos protein expression in the dorsal striatum induced by haloperidol (0.6mg/kg). We also evaluated if these effects occur through the facilitation of 5-HT1A receptor-mediated neurotransmission. For this, male Swiss mice were treated with CBD and haloperidol systemically and then subjected to the catalepsy test. Independent groups of animals were also treated with the 5-HT1A receptor antagonist WAY100635 (0.1mg/kg). As expected, haloperidol induced catalepsy throughout the experiments, an effect that was prevented by systemic CBD treatment 30min before haloperidol administration. Also, CBD, administered 2.5h after haloperidol, reversed haloperidol-induced catalepsy. Haloperidol also increased c-Fos protein expression in the dorsolateral striatum, an effect attenuated by previous CBD administration. CBD effects on catalepsy and c-Fos protein expression induced by haloperidol were blocked by the 5-HT1A receptor antagonist. We also evaluated the effects of CBD (60nmol) injection into the dorsal striatum on haloperidol-induced catalepsy. Similar to systemic administration, this treatment reduced catalepsy induced by haloperidol. Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT1A receptors. Copyright © 2016 Elsevier B.V. All rights reserved.

Individual variations in maternal care early in life correlate with later life decision-making and c-fos expression in prefrontal subregions of rats.

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Felisa N van Hasselt

Full Text Available Early life adversity affects hypothalamus-pituitary-adrenal axis activity, alters cognitive functioning and in humans is thought to increase the vulnerability to psychopathology--e.g. depression, anxiety and schizophrenia--later in life. Here we investigated whether subtle natural variations among individual rat pups in the amount of maternal care received, i.e. differences in the amount of licking and grooming (LG, correlate with anxiety and prefrontal cortex-dependent behavior in young adulthood. Therefore, we examined the correlation between LG received during the first postnatal week and later behavior in the elevated plus maze and in decision-making processes using a rodent version of the Iowa Gambling Task (rIGT. In our cohort of male and female animals a high degree of LG correlated with less anxiety in the elevated plus maze and more advantageous choices during the last 10 trials of the rIGT. In tissue collected 2 hrs after completion of the task, the correlation between LG and c-fos expression (a marker of neuronal activity was established in structures important for IGT performance. Negative correlations existed between rIGT performance and c-fos expression in the lateral orbitofrontal cortex, prelimbic cortex, infralimbic cortex and insular cortex. The insular cortex correlations between c-fos expression and decision-making performance depended on LG background; this was also true for the lateral orbitofrontal cortex in female rats. Dendritic complexity of insular or infralimbic pyramidal neurons did not or weakly correlate with LG background. We conclude that natural variations in maternal care received by pups may significantly contribute to later-life decision-making and activity of underlying brain structures.

Epigenetic regulation of Arc and c-Fos in the hippocampus after acute electroconvulsive stimulation in the rat

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Dyrvig, Mads; Hansen, Henrik H; Christiansen, Søren Hofman Oliveira

2012-01-01

Electroconvulsive stimulation (ECS) remains one of the most effective treatments of major depression. However, the underlying molecular changes still remain to be elucidated. Since ECS causes rapid and significant changes in gene expression we have looked at epigenetic regulation of two important...... of the important epigenetic marks associated with gene activation. We show increased H4Ac at the c-Fos promoter at 1 h post-ECS. Surprisingly, we also observed a significant increase in DNA methylation of the Arc gene promoter at 24 h post-ECS. DNA methylation, which is responsible for gene silencing, is a rather...

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...

The evolution of C/O in dwarf galaxies from Hubble Space Telescope FOS observations

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Garnett, D. R.; Skillman, E. D.; Dufour, R. J.; Peimbert, M.; Torres-Peimbert, S.; Terlevich, R.; Terlevich, E.; Shields, G. A.

1995-01-01

We present UV observations of seven H II regions in low-luminosity dwarf irregular galaxies and the Magellanic Clouds obtained with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) in order to measure the C/O abundance ratio in the interstellar medium (ISM) of those galaxies. We measure both O III 1666 A and C III 1909 A in our spectra, enabling us to determine C(+2)/O(+2) with relatively small uncertainties. The results from our HST observations show a continuous increase in C/O with increasing O/H, consistent with a power law having an index of 0.43 +/- 0.09 over the range -4.7 to -3.6 in log (O/H). One possible interpretation of this trend is that the most metal-poor galaxies are the youngest and dominated by the products of early enrichment by massive stars, while more metal-rich galaxies show increasing, delayed contributions of carbon from intermediate-mass stars. Our results also suggest that it may not be appropiate to combine abundances in irregular galaxies with those in spiral galaxies to study the evolution of chemical abundances. Our measured C/O ratios in the most metal-poor galaxies are consistent with predictions of nucleosynthesis from massive stars for Weaver & Woosley's best estimate for the 12C(alpha, gamma) 16O nuclear reaction rate, assuming negligible contanmination from carbon produced in intermediate-mass stars in these galaxies. We detect a weak N III 1750 A multiplet in SMC N88A and obtain interesting upper limits for two other objects. Our 2 sigma uppr limits on the 1750 A feature indicate that the N(+2)/O(+2) ratios in these objects are not significantly larger than the N(+)/O(+) ratios measured from optical spectra. This behavior is consistent with predictions of photionization models, although better detections of N III are needed to confirm the results.

Mapping the areas sensitive to long-term endotoxin tolerance in the rat brain: a c-fos mRNA study.

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Vallès, Astrid; Martí, Octavi; Armario, Antonio

2005-06-01

We have recently found that a single endotoxin administration to rats reduced the hypothalamic-pituitary-adrenal response to another endotoxin administration 4 weeks later, which may be an example of the well-known phenomenon of endotoxin tolerance. However, the time elapsed between the two doses of endotoxin was long enough to consider the above results as an example of late tolerance, whose mechanisms are poorly characterized. To know if the brain plays a role in this phenomenon and to characterize the putative areas involved, we compared the c-fos mRNA response after a final dose of endotoxin in animals given vehicle or endotoxin 4 weeks before. Endotoxin caused a widespread induction of c-fos mRNA in the brain, similar to that previously reported by other laboratories. Whereas most of the brain areas were not sensitive to the previous experience with endotoxin, a few showed a reduced response in endotoxin-pretreated rats: the parvocellular and magnocellular regions of the paraventricular hypothalamic nucleus, the central amygdala, the lateral division of the bed nucleus and the locus coeruleus. We hypothesize that late tolerance to endotoxin may involve plastic changes in the brain, likely to be located in the central amygdala. The reduced activation of the central amygdala in rats previously treated with endotoxin may, in turn, reduce the activation of other brain areas, including the hypothalamic paraventicular nucleus.

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.

Repeated exposure to cat urine induces complex behavioral, hormonal, and c-fos mRNA responses in Norway rats ( Rattus norvegicus)

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Yin, Baofa; Gu, Chen; Lu, Yi; Hegab, Ibrahim M.; Yang, Shengmei; Wang, Aiqin; Wei, Wanhong

2017-08-01

Prey species show specific adaptations that allow recognition, avoidance, and defense against predators. This study was undertaken to investigate the processing of a chronic, life-threatening stimulus to Norway rats ( Rattus norvegicus). One hundred forty-four Norway rats were tested by repeated presentation of cat urine for 1 h at different days in a defensive withdrawal apparatus. Rats exposed to urine for short periods showed significantly larger defensive behavioral and medial hypothalamic c-fos messenger RNA (mRNA) responses than other groups. These defensive responses habituated shortly after the presentation of cat urine. Serum levels of adrenocorticotropic hormone and corticosterone increased significantly when animals were repeatedly exposed to cat urine. However, the hormonal responses took longer to habituate than the behavioral and molecular responses did. We conclude that the behavioral and c-fos mRNA responses are "primed" for habituation to repeated exposures to cat urine, while the hormonal responses show "resistance." The results support our hypothesis that the strongest anti-predator responses at three levels would occur during short-term exposure to cat urine and that these responses would subsequently disappear on prolonged exposure. This study assists understanding the way in which the different levels of defensive responses are integrated and react during chronic stress.

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

International Nuclear Information System (INIS)

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

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

Identification of cytotoxic drugs that selectively target tumor cells with MYC overexpression.

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Anna Frenzel

Full Text Available Expression of MYC is deregulated in a wide range of human cancers, and is often associated with aggressive disease and poorly differentiated tumor cells. Identification of compounds with selectivity for cells overexpressing MYC would hence be beneficial for the treatment of these tumors. For this purpose we used cell lines with conditional MYCN or c-MYC expression, to screen a library of 80 conventional cytotoxic compounds for their ability to reduce tumor cell viability and/or growth in a MYC dependent way. We found that 25% of the studied compounds induced apoptosis and/or inhibited proliferation in a MYC-specific manner. The activities of the majority of these were enhanced both by c-MYC or MYCN over-expression. Interestingly, these compounds were acting on distinct cellular targets, including microtubules (paclitaxel, podophyllotoxin, vinblastine and topoisomerases (10-hydroxycamptothecin, camptothecin, daunorubicin, doxorubicin, etoposide as well as DNA, RNA and protein synthesis and turnover (anisomycin, aphidicholin, gliotoxin, MG132, methotrexate, mitomycin C. Our data indicate that MYC overexpression sensitizes cells to disruption of specific pathways and that in most cases c-MYC and MYCN overexpression have similar effects on the responses to cytotoxic compounds. Treatment of the cells with topoisomerase I inhibitors led to down-regulation of MYC protein levels, while doxorubicin and the small molecule MYRA-A was found to disrupt MYC-Max interaction. We conclude that the MYC pathway is only targeted by a subset of conventional cytotoxic drugs currently used in the clinic. Elucidating the mechanisms underlying their specificity towards MYC may be of importance for optimizing treatment of tumors with MYC deregulation. Our data also underscores that MYC is an attractive target for novel therapies and that cellular screenings of chemical libraries can be a powerful tool for identifying compounds with a desired biological activity.

Ghrelin agonists impact on Fos protein expression in brain areas related to food intake regulation in male C57BL/6 mice.

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Pirnik, Z; Bundziková, J; Holubová, M; Pýchová, M; Fehrentz, J A; Martinez, J; Zelezná, B; Maletínská, L; Kiss, A

2011-11-01

Many peripheral substances, including ghrelin, induce neuronal activation in the brain. In the present study, we compared the effect of subcutaneously administered ghrelin and its three stable agonists: Dpr(3)ghr ([Dpr(N-octanoyl)(3)] ghrelin) (Dpr - diaminopropionic acid), YA GHRP-6 (H-Tyr-Ala-His-DTrp-Ala-Trp-DPhe-Lys-NH(2)), and JMV1843 (H-Aib-DTrp-D-gTrp-CHO) on the Fos expression in food intake-responsive brain areas such as the hypothalamic paraventricular (PVN) and arcuate (ARC) nuclei, the nucleus of the solitary tract (NTS), and area postrema (AP) in male C57BL/6 mice. Immunohistochemical analysis showed that acute subcutaneous dose of each substance (5mg/kg b.w.), which induced a significant food intake increase, elevated Fos protein expression in all brain areas studied. Likewise ghrelin, each agonist tested induced distinct Fos expression overall the PVN. In the ARC, ghrelin and its agonists specifically activated similarly distributed neurons. Fos occurrence extended from the anterior (aARC) to middle (mARC) ARC region. In the latter part of the ARC, the Fos profiles were localized bilaterally, especially in the ventromedial portions of the nucleus. In the NTS, all substances tested also significantly increased the number of Fos profiles in neurons, which also revealed specific location, i.e., in the NTS dorsomedial subnucleus (dmNTS) and the area subpostrema (AsP). In addition, cells located nearby the NTS, in the AP, also revealed a significant increase in number of Fos-activated cells. These results demonstrate for the first time that ghrelin agonists, regardless of their different chemical nature, have a significant and similar activating impact on specific groups of neurons that can be a part of the circuits involved in the food intake regulation. Therefore there is a real potency for ghrelin agonists to treat cachexia and food intake disorders. Thus, likewise JMV1843, the other ghrelin agonists represent substances that might be involved in

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.

Loss of MYC confers resistance to doxorubicin-induced apoptosis by preventing the activation of multiple serine protease- and caspase-mediated pathways

DEFF Research Database (Denmark)

Grassilli, Emanuela; Ballabeni, Andrea; Maellaro, Emilia

2004-01-01

c-Myc plays an essential role in proliferation, differentiation, and apoptosis. Because of its relevance to cancer, most studies have focused on the cellular consequences of c-Myc overexpression. Here, we address the role of physiological levels of c-Myc in drug-induced apoptosis. By using c-MYC ...... support a model in which doxorubicin simultaneously triggers multiple c-Myc-dependent apoptosis pathways....

Molecular cloning and analysis of Myc modulator 1 (Mm-1 from Bufo gargarizans (Amphibia: Anura

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Ning Wang

2010-02-01

Full Text Available The protein of Myc modulator 1 (Mm-1 has been reported to repress the transcriptional activity of the proto-oncogene c-Myc in humans. Moreover, it was shown to be the subunit 5 of human prefoldin (PFD. So far, this gene and its homologs have been isolated and sequenced in many organisms, such as mammals and fish, but has not been sequenced for any amphibian or reptile. In order to better understand the function and evolution of Mm-1, we isolated a full-length Mm-1 cDNA (BgMm-1, GenBank accession no. EF211947 from Bufo gargarizans (Cantor, 1842 using RACE (rapid amplification of cDNA ends methods. Mm-1 in B. gargarizans is 755 bp long, comprising an open reading frame (ORF of 459 bp encoding 152 amino acids. The amino acid sequence had a prefoldin α-like domain, partially including a typical putative leucine zipper motif. BgMm-1 showed high similarity to its homolog of Mus musculus Linnaeus, 1758 (82% and Homo sapiens Linnaeus, 1758 MM-1 isoform a (81% at the amino acid level. The protein secondary structure modeled with the SWISS MODEL server revealed that there were two α-helices and four b-strands in BgMm-1 as its human orthologue, and both proteins belonged to the a class of PFD family. The phylogenetic relationships of Mm-1s from lower archaea to high mammals was consistent with the evolution of species, meanwhile the cluster result was consistent with the multiple alignment and the sequence identity analysis. RT-PCR (reverse transcriptase-polymerase chain reaction analysis demonstrated that BgMm-1 expressed widely in ten tissues of adult toad. These results can be helpful for the further investigation on the evolution of Mm-1.

C/EBPβ Mediates Growth Hormone-Regulated Expression of Multiple Target Genes

Science.gov (United States)

Cui, Tracy X.; Lin, Grace; LaPensee, Christopher R.; Calinescu, Anda-Alexandra; Rathore, Maanjot; Streeter, Cale; Piwien-Pilipuk, Graciela; Lanning, Nathan; Jin, Hui; Carter-Su, Christin; Qin, Zhaohui S.

2011-01-01

Regulation of c-Fos transcription by GH is mediated by CCAAT/enhancer binding protein β (C/EBPβ). This study examines the role of C/EBPβ in mediating GH activation of other early response genes, including Cyr61, Btg2, Socs3, Zfp36, and Socs1. C/EBPβ depletion using short hairpin RNA impaired responsiveness of these genes to GH, as seen for c-Fos. Rescue with wild-type C/EBPβ led to GH-dependent recruitment of the coactivator p300 to the c-Fos promoter. In contrast, rescue with C/EBPβ mutated at the ERK phosphorylation site at T188 failed to induce GH-dependent recruitment of p300, indicating that ERK-mediated phosphorylation of C/EBPβ at T188 is required for GH-induced recruitment of p300 to c-Fos. GH also induced the occupancy of phosphorylated C/EBPβ and p300 on Cyr61, Btg2, and Socs3 at predicted C/EBP-cAMP response element-binding protein motifs in their promoters. Consistent with a role for ERKs in GH-induced expression of these genes, treatment with U0126 to block ERK phosphorylation inhibited their GH-induced expression. In contrast, GH-dependent expression of Zfp36 and Socs1 was not inhibited by U0126. Thus, induction of multiple early response genes by GH in 3T3-F442A cells is mediated by C/EBPβ. A subset of these genes is regulated similarly to c-Fos, through a mechanism involving GH-stimulated ERK 1/2 activation, phosphorylation of C/EBPβ, and recruitment of p300. Overall, these studies suggest that C/EBPβ, like the signal transducer and activator of transcription proteins, regulates multiple genes in response to GH. PMID:21292824

Calcimimetic R568 inhibits tetrodotoxin-sensitive colonic electrolyte secretion and reduces c-fos expression in myenteric neurons.

Science.gov (United States)

Sun, Xiangrong; Tang, Lieqi; Winesett, Steven; Chang, Wenhan; Cheng, Sam Xianjun

2018-02-01

Calcium-sensing receptor (CaSR) is expressed on neurons of both submucosal and myenteric plexuses of the enteric nervous system (ENS) and the CaSR agonist R568 inhibited Cl - secretion in intestine. The purpose of this study was to localize the primary site of action of R568 in the ENS and to explore how CaSR regulates secretion through the ENS. Two preparations of rat proximal and distal colon were used. The full-thickness preparation contained both the submucosal and myenteric plexuses, whereas for the "stripped" preparation the myenteric plexus with the muscle layers was removed. Both preparations were mounted onto Ussing chambers and Cl - secretory responses were compared by measuring changes in short circuit current (I sc ). Two tissue-specific CaSR knockouts (i.e., neuron-specific vs. enterocyte-specific) were generated to compare the effect of R568 on expression of c-fos protein in myenteric neurons by immunocytochemistry. In full-thickness colons, tetrodotoxin (TTX) inhibited I sc , both in proximal and distal colons. A nearly identical inhibition was produced by R568. However, in stripped preparations, while the effect of TTX on I sc largely remained, the effect of R568 was nearly completely eliminated. In keeping with this, R568 reduced c-fos protein expression only in myenteric neurons of wild type mice and mutant mice that contained CaSR in neurons (i.e., villin Cre/Casr flox/flox mice), but not in myenteric neurons of nestin Cre/Casr flox/flox mice in which neuronal cell CaSR was eliminated. These results indicate that R568 exerts its anti-secretory effects predominantly via CaSR-mediated inhibition of neuronal activity in the myenteric plexus. Published by Elsevier Inc.

The Effects of Aronia melanocarpa 'Viking' Extracts in Attenuating RANKL-Induced Osteoclastic Differentiation by Inhibiting ROS Generation and c-FOS/NFATc1 Signaling.

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Ghosh, Mithun; Kim, In Sook; Lee, Young Min; Hong, Seong Min; Lee, Taek Hwan; Lim, Ji Hong; Debnath, Trishna; Lim, Beong Ou

2018-03-08

This study aimed to determine the anti-osteoclastogenic effects of extracts from Aronia melanocarpa 'Viking' (AM) and identify the underlying mechanisms in vitro. Reactive oxygen species (ROS) are signal mediators in osteoclast differentiation. AM extracts inhibited ROS production in RAW 264.7 cells in a dose-dependent manner and exhibited strong radical scavenging activity. The extracts also attenuated the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts. To attain molecular insights, the effect of the extracts on the signaling pathways induced by receptor activator of nuclear factor kappa B ligand (RANKL) were also investigated. RANKL triggers many transcription factors through the activation of mitogen-activated protein kinase (MAPK) and ROS, leading to the induction of osteoclast-specific genes. The extracts significantly suppressed RANKL-induced activation of MAPKs, such as extracellular signal-regulated kinase (ERK), c-Jun- N -terminal kinase (JNK) and p38 and consequently led to the downregulation of c-Fos and nuclear factor of activated T cells 1 (NFATc1) protein expression which ultimately suppress the activation of the osteoclast-specific genes, cathepsin K, TRAP, calcitonin receptor and integrin β₃. In conclusion, our findings suggest that AM extracts inhibited RANKL-induced osteoclast differentiation by downregulating ROS generation and inactivating JNK/ERK/p38, nuclear factor kappa B (NF-κB)-mediated c-Fos and NFATc1 signaling pathway.

Wedelolactone enhances osteoblastogenesis by regulating Wnt/β-catenin signaling pathway but suppresses osteoclastogenesis by NF-κB/c-fos/NFATc1 pathway.

Science.gov (United States)

Liu, Yan-Qiu; Hong, Zhi-Lai; Zhan, Li-Bin; Chu, Hui-Ying; Zhang, Xiao-Zhe; Li, Guo-Hui

2016-08-25

Bone homeostasis is maintained by formation and destruction of bone, which are two processes tightly coupled and controlled. Targeting both stimulation on bone formation and suppression on bone resorption becomes a promising strategy for treating osteoporosis. In this study, we examined the effect of wedelolactone, a natural product from Ecliptae herba, on osteoblastogenesis as well as osteoclastogenesis. In mouse bone marrow mesenchymal stem cells (BMSC), wedelolactone stimulated osteoblast differentiation and bone mineralization. At the molecular level, wedelolactone directly inhibited GSK3β activity and enhanced the phosphorylation of GSK3β, thereafter stimulated the nuclear translocation of β-catenin and runx2. The expression of osteoblastogenesis-related marker gene including osteorix, osteocalcin and runx2 increased. At the same concentration range, wedelolactone inhibited RANKL-induced preosteoclastic RAW264.7 actin-ring formation and bone resorption pits. Further, wedelolactone blocked NF-kB/p65 phosphorylation and abrogated the NFATc1 nuclear translocation. As a result, osteoclastogenesis-related marker gene expression decreased, including c-src, c-fos, and cathepsin K. In ovariectomized mice, administration of wedelolactone prevented ovariectomy-induced bone loss by enhancing osteoblast activity and inhibiting osteoclast activity. Together, these data demonstrated that wedelolactone facilitated osteoblastogenesis through Wnt/GSK3β/β-catenin signaling pathway and suppressed RANKL-induced osteoclastogenesis through NF-κB/c-fos/NFATc1 pathway. These results suggested that wedelolacone could be a novel dual functional therapeutic agent for osteoporosis.

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

Molecular Mechanisms of Cigarette Smoke-Induced Proliferation of Lung Cells and Prevention by Vitamin C

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Neekkan Dey

2011-01-01

Full Text Available Lung cancer is the leading cause of cancer dearth. Cigarette smoking is the strongest risk factor for developing lung cancer, which is conceivably initiated by proliferation. Here, we show that low concentration of aqueous extract of cigarette smoke (AECS causes excessive proliferation of human lung epithelial cells (A549 without any apoptotic cell death. The causative factor responsible for AECS-induced proliferation has been identified as p-benzoquinone (p-BQ. Coimmunoprecipitation and immunoblot experiments indicate that p-BQ binds with epidermal growth factor receptor (EGFR. However, in contrast to EGF, it causes aberrant phosphorylation of EGFR that lacks c-Cbl-mediated ubiquitination and degradation resulting in persistent activation of EGFR. This is followed by activation of Hras + Kras and the downstream survival and proliferative signaling molecules Akt and ERK1/2, as well as the nuclear transcription factors c-Myc and c-Fos. Vitamin C and/or antibody to p-BQ prevents AECS/p-BQ-induced proliferation of lung cells apparently by inactivating p-BQ and thereby preventing activation of EGFR and the downstream signaling molecules. The results suggest that vitamin C and/or antibody to p-BQ may provide a novel intervention for preventing initiation of lung cancer in smokers.

Differential cortical c-Fos and Zif-268 expression after object and spatial memory processing in a standard or episodic-like object recognition task

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Flávio F Barbosa

2013-08-01

Full Text Available Episodic memory reflects the capacity to recollect what, where and when a specific event happened in an integrative manner. Animal studies have suggested that the medial temporal lobe and the medial pre-frontal cortex are important for episodic-like memory formation. The goal of present study was to evaluate whether there are different patterns of expression of the immediate early genes c-Fos and Zif-268 in these cortical areas after rats are exposed to object recognition tasks with different cognitive demands. Male rats were randomly assigned to five groups: home cage control (CTR-HC, empty open field (CTR-OF, open field with one object (CTR-OF + Obj, novel object recognition task (OR and episodic-like memory task (ELM and were killed one hour after the last behavioral procedure. Rats were able to discriminate the objects in the OR task. In the ELM task, rats showed spatial (but not temporal discrimination of the objects. We found an increase in the c-Fos expression in the dorsal dentate gyrus (DG and in the perirhinal cortex (PRh in the OR and ELM groups. The OR group also presented an increase of c-Fos expression in the medial prefrontal cortex (mPFC. Additionally, the OR and ELM groups had increased expression of Zif-268 in the mPFC. Moreover, Zif-268 was increased in the dorsal CA1 and perirhinal cortex only in the ELM group. In conclusion, the pattern of activation was different in tasks with different cognitive demands. Accordingly, correlation tests suggest the engagement of different neural networks in the object recognition tasks used. Specifically, perirhinal-dentate gyrus co-activation was detected after the what-where memory retrieval, but not after the novel object recognition task. Both regions correlated with the respective behavioral outcome. These findings can be helpful in the understanding of the neural networks underlying memory tasks with different cognitive demands.

Exposure to an open-field arena increases c-Fos expression in a subpopulation of neurons in the dorsal raphe nucleus, including neurons projecting to the basolateral amygdaloid complex

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Hale, M.W.; Hay-Schmidt, A.; Mikkelsen, J.D.

2008-01-01

Serotonergic systems in the dorsal raphe nucleus are thought to play an important role in the regulation of anxiety states. To investigate responses of neurons in the dorsal raphe nucleus to a mild anxiety-related stimulus, we exposed rats to an open-field, under low-light or high-light conditions....... Treatment effects on c-Fos expression in serotonergic and non-serotonergic cells in the midbrain raphe nuclei were determined 2 h following open-field exposure or home cage control (CO) conditions. Rats tested under both light conditions responded with increases in c-Fos expression in serotonergic neurons...... within subdivisions of the midbrain raphe nuclei compared with CO rats. However, the total numbers of serotonergic neurons involved were small suggesting that exposure to the open-field may affect a subpopulation of serotonergic neurons. To determine if exposure to the open-field activates a subset...

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.

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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.

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

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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.

The Effects of Aronia melanocarpa ‘Viking’ Extracts in Attenuating RANKL-Induced Osteoclastic Differentiation by Inhibiting ROS Generation and c-FOS/NFATc1 Signaling

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Mithun Ghosh

2018-03-01

Full Text Available This study aimed to determine the anti-osteoclastogenic effects of extracts from Aronia melanocarpa ‘Viking’ (AM and identify the underlying mechanisms in vitro. Reactive oxygen species (ROS are signal mediators in osteoclast differentiation. AM extracts inhibited ROS production in RAW 264.7 cells in a dose-dependent manner and exhibited strong radical scavenging activity. The extracts also attenuated the number of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts. To attain molecular insights, the effect of the extracts on the signaling pathways induced by receptor activator of nuclear factor kappa B ligand (RANKL were also investigated. RANKL triggers many transcription factors through the activation of mitogen-activated protein kinase (MAPK and ROS, leading to the induction of osteoclast-specific genes. The extracts significantly suppressed RANKL-induced activation of MAPKs, such as extracellular signal-regulated kinase (ERK, c-Jun-N-terminal kinase (JNK and p38 and consequently led to the downregulation of c-Fos and nuclear factor of activated T cells 1 (NFATc1 protein expression which ultimately suppress the activation of the osteoclast-specific genes, cathepsin K, TRAP, calcitonin receptor and integrin β3. In conclusion, our findings suggest that AM extracts inhibited RANKL-induced osteoclast differentiation by downregulating ROS generation and inactivating JNK/ERK/p38, nuclear factor kappa B (NF-κB-mediated c-Fos and NFATc1 signaling pathway.

Fos and jun proteins are specifically expressed during differentiation of human keratinocytes.

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Mehic, Denis; Bakiri, Latifa; Ghannadan, Minoo; Wagner, Erwin F; Tschachler, Erwin

2005-01-01

Activator protein 1 (AP-1) proteins play key roles in the regulation of cell proliferation and differentiation. In this study we investigated the expression of Fos and Jun proteins in different models of terminal differentiation of human keratinocytes and in skin from psoriasis patients. All Jun and Fos proteins, with the exception of FosB, were efficiently expressed in keratinocytes in monolayer cultures. In contrast, in normal epidermis as well as in organotypic epidermal cultures, the expression pattern of AP-1 proteins was dependent on the differentiation stage. Fos proteins were readily detected in nuclei of keratinocytes of basal and suprabasal layers. JunB and JunD were expressed in all layers of normal epidermis. Interestingly, expression of c-Jun started suprabasally, then disappeared and became detectable again in distinct cells of the outermost granular layer directly at the transition zone to the stratum corneum. In psoriatic epidermis, c-Jun expression was prominent in both hyperproliferating basal and suprabasal keratinocytes, whereas c-Fos expression was unchanged. These data indicate that AP-1 proteins are expressed in a highly specific manner during terminal differentiation of keratinocytes and that the enhanced expression of c-Jun in basal and suprabasal keratinocytes might contribute to the pathogenesis of psoriasis.

Cellular oncogene expression following exposure of mice to γ-rays

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Anderson, A.; Woloschak, G.E.

1991-01-01

We examined the effects of total body exposure of BCF1 mice to γ-rays (300 cGy) in modulating expression of cellular oncogenes in both gut and liver tissues. We selected specific cellular oncogenes (c-fos, c-myc, c-src, and c-H-ras), based on their normal expression in liver and gut tissues from untreated mice. As early as 5 min. following whole body exposure of BCF1 mice to γ-rays we detected induction of mRNA specific for c-src and c-H-ras in both liver and gut tissues. c-fos RNA was slightly decreased in accumulation in gut but was unaffected in liver tissue from irradiated mice relative to untreated controls. c-myc mRNA accumulation was unaffected in all tissues examined. These experiments document that modulation of cellular oncogene expression can occur as an early event in tissues following irradiation and suggest that this modulation may play a role in radiation-induced carcinogenesis

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

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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.

Anti-apoptotic A1 is not essential for lymphoma development in Eµ-Myc mice but helps sustain transplanted Eµ-Myc tumour cells.

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Mensink, Mark; Anstee, Natasha S; Robati, Mikara; Schenk, Robyn L; Herold, Marco J; Cory, Suzanne; Vandenberg, Cassandra J

2018-03-01

The transcription factor c-MYC regulates a multiplicity of genes involved in cellular growth, proliferation, metabolism and DNA damage response and its overexpression is a hallmark of many tumours. Since MYC promotes apoptosis under conditions of stress, such as limited availability of nutrients or cytokines, MYC-driven cells are very much dependent on signals that inhibit cell death. Stress signals trigger apoptosis via the pathway regulated by opposing fractions of the BCL-2 protein family and previous genetic studies have shown that the development of B lymphoid tumours in Eµ-Myc mice is critically dependent on expression of pro-survival BCL-2 relatives MCL-1, BCL-W and, to a lesser extent, BCL-X L , but not BCL-2 itself, and that sustained growth of these lymphomas is dependent on MCL-1. Using recently developed mice that lack expression of all three functional pro-survival A1 genes, we show here that the kinetics of lymphoma development in Eµ-Myc mice and the competitive repopulation capacity of Eµ-Myc haemopoietic stem and progenitor cells is unaffected by the absence of A1. However, conditional loss of a single remaining functional A1 gene from transplanted A1-a -/- A1-b fl/fl A1-c -/- Eµ-Myc lymphomas slowed their expansion, significantly extending the life of the transplant recipients. Thus, A1 contributes to the survival of malignant Eµ-Myc-driven B lymphoid cells. These results strengthen the case for BFL-1, the human homologue of A1, being a valid target for drug development for MYC-driven tumours.

Exposure to high- and low-light conditions in an open-field test of anxiety increases c-Fos expression in specific subdivisions of the rat basolateral amygdaloid complex.

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Hale, Matthew W; Bouwknecht, J Adriaan; Spiga, Francesca; Shekhar, Anantha; Lowry, Christopher A

2006-12-11

Anxiety states and anxiety-related behaviors appear to be regulated by a distributed and highly interconnected system of forebrain structures including the basolateral amygdaloid complex (basolateral amygdala). Despite a wealth of research examining the role of the basolateral amygdala in anxiety-related behaviors and anxiety states, the specific subdivisions of the basolateral amygdala that are involved in responses to anxiogenic stimuli have not been examined. In this study, we investigated the effects of exposure to a novel open-field environment, with either low- or high-levels of illumination, on expression of the protein product of the immediate-early gene c-Fos in subdivisions of the rat basolateral amygdala. The subdivisions studied included the lateral, ventrolateral and ventromedial parts of the lateral amygdaloid nucleus, the anterior, posterior and ventral parts of the basolateral amygdaloid nucleus and the anterior and posterior part of the basomedial amygdaloid nucleus. Small increases in the number of c-Fos-immunoreactive cells were observed in several, but not all, of the subdivisions of the basolateral amygdala studied following exposure of rats to either the high- or low-light conditions, compared to home cage or handled control groups. Open-field exposure in both the high- and low-light conditions resulted in a marked increase in c-Fos expression in the anterior part of the basolateral amygdaloid nucleus compared to either home cage or handled control groups. These findings point toward anatomical and functional heterogeneity within the basolateral amygdaloid complex and an important role of the anterior part of the basolateral amygdaloid nucleus in the neural mechanisms underlying physiological or behavioral responses to this anxiety-related stimulus.

Fos and serotonin immunoreactivity in the raphe nuclei of the cat during carbachol-induced active sleep: a double-labeling study.

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Yamuy, J; Sampogna, S; López-Rodríguez, F; Luppi, P H; Morales, F R; Chase, M H

1995-07-01

The microinjection of carbachol into the nucleus pontis oralis produces a state which is polygraphically and behaviorally similar to active sleep (rapid eye movement sleep). In the present study, using double-labeling techniques for serotonin and the protein product of c-fos (Fos), we sought to examine whether immunocytochemically identified serotonergic neurons of the raphe nuclei of the cat were activated, as indicated by their expression of c-fos, during this pharmacologically-induced behavioral state (active sleep-carbachol). Compared with control cats, which were injected with saline, active sleep-carbachol cats exhibited a significantly greater number of c-fos-expressing neurons in the raphe dorsalis, magnus and pallidus. Whereas most of the c-fos-expressing neurons in the raphe dorsalis were small, those in the raphe magnus were medium-sized and in the raphe pallidus they were small and medium-sized. The mean number of serotonergic neurons that expressed c-fos (i.e. double-labeled cells) was similar in control and active sleep-carbachol cats. These data indicate that there is an increased number of non-serotonergic, c-fos-expressing neurons in the raphe dorsalis, magnus and pallidus during the carbachol-induced state.(ABSTRACT TRUNCATED AT 250 WORDS)

MYC is a metastasis gene for non-small-cell lung cancer.

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Ulf R Rapp

Full Text Available BACKGROUND: Metastasis is a process by which cancer cells learn to form satellite tumors in distant organs and represents the principle cause of death of patients with solid tumors. NSCLC is the most lethal human cancer due to its high rate of metastasis. METHODOLOGY/PRINCIPAL FINDINGS: Lack of a suitable animal model has so far hampered analysis of metastatic progression. We have examined c-MYC for its ability to induce metastasis in a C-RAF-driven mouse model for non-small-cell lung cancer. c-MYC alone induced frank tumor growth only after long latency at which time secondary mutations in K-Ras or LKB1 were detected reminiscent of human NSCLC. Combination with C-RAF led to immediate acceleration of tumor growth, conversion to papillary epithelial cells and angiogenic switch induction. Moreover, addition of c-MYC was sufficient to induce macrometastasis in liver and lymph nodes with short latency associated with lineage switch events. Thus we have generated the first conditional model for metastasis of NSCLC and identified a gene, c-MYC that is able to orchestrate all steps of this process. CONCLUSIONS/SIGNIFICANCE: Potential markers for detection of metastasis were identified and validated for diagnosis of human biopsies. These markers may represent targets for future therapeutic intervention as they include genes such as Gata4 that are exclusively expressed during lung development.

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

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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.

Effect of MgSO4 on the expression of C-fos gene and the abilities of learning and memory in the rat brain with radiation induced injuries

International Nuclear Information System (INIS)

Zhang Wei; Wang Rui; Wang Lili; Zhou Juying; Tu Yu; Zou Rong; Zhou Weifang

2009-01-01

Objective: To investigate the effect of magnesium sulfate (MgSO 4 ) on the nerves function after hemisphere irradiation and explore possible mechanism of the effect. Methods: Mature Sprague-Dawley rats were randomly divided into 3 groups: blank control group (n = 26), experimental control group (n = 32) and experimental group (n = 32). To selecte rats randomly from the experimental control group and the experimental therapy group for 1/2 brain irradiation to a single-fraction maximal dose of 20 Gy using 5 MeV electrons. Magnesium sulfate was injected intraperitoneally into the rats that from the experimental group before and after irradiation for total seven times. The expression of c-fos gene was observed in the hippocampal formation of the rat brain with the immunofluorescence technique in 24 h after irradiation. The learning and memory results in Y-maze test were detected 8 weeks after irradiation respectively with the other rats and then had the pathomorphology observation. Results: Compared with the blank control group, the number of c-fos immunopositive cells in the hippocampal formation of experimental control group were increased markedly (P<0.01), and the learning and memory results of Y-maze test in the irradiation control group declined significantly (P<0.01). Compared with the irradiation control group, the experimental group's Fos immunopositive cells decreased significantly (P<0.05), and also the cognitive function of learning attempt times (at 4 and 8 weeks, P<0.01) and memory reappearance times (P<0.05) were significantly different from that in the irradiation control group. Conclusion: Magnesium sulfate can promote the recovery of the rats' cognitive impairment in the early stage after irradiation, and may play a role of protecting hippocampus neurons by the way of decreasing the expression of Fos protin in hippocampal formation. (authors)

Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.

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Potvin, Eric; Beuret, Laurent; Cadrin-Girard, Jean-François; Carter, Marcelle; Roy, Sophie; Tremblay, Michel; Charron, Jean

2010-11-01

The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.2 are sufficient to reproduce the N-myc embryonic expression profile in developing branchial arches and limb buds. These sequences encompass several regulatory elements dispersed throughout the N-myc locus, including an upstream limb bud enhancer, a downstream somite enhancer, a branchial arch enhancer in the second intron, and a negative regulatory element in the first intron. N-myc expression in the limb buds is under the dominant control of the limb bud enhancer. The expression in the branchial arches necessitates the interplay of three regulatory domains. The branchial arch enhancer cooperates with the somite enhancer region to prevent an inhibitory activity contained in the first intron. The characterization of the branchial arch enhancer has revealed a specific role of the transcription factor GATA3 in the regulation of N-myc expression. Together, these data demonstrate that correct N-myc developmental expression is achieved via cooperation of multiple positive and negative regulatory elements.

MYC activates stem-like cell potential in hepatocarcinoma by a p53-dependent mechanism

DEFF Research Database (Denmark)

Akita, Hirofumi; Marquardt, Jens U; Durkin, Marian E

2014-01-01

Activation of c-MYC is an oncogenic hallmark of many cancers including liver cancer, and is associated with a variety of adverse prognostic characteristics. Despite a causative role during malignant transformation and progression in hepatocarcinogenesis, consequences of c-MYC activation for the b...

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.

Maternal neglect with reduced depressive-like behavior and blunted c-fos activation in Brattleboro mothers, the role of central vasopressin.

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Fodor, Anna; Klausz, Barbara; Pintér, Ottó; Daviu, Nuria; Rabasa, Cristina; Rotllant, David; Balazsfi, Diana; Kovacs, Krisztina B; Nadal, Roser; Zelena, Dóra

2012-09-01

Early mother-infant relationships exert important long-term effects in offspring and are disturbed by factors such as postpartum depression. We aimed to clarify if lack of vasopressin influences maternal behavior paralleled by the development of a depressive-like phenotype. We compared vasopressin-deficient Brattleboro mothers with heterozygous and homozygous normal ones. The following parameters were measured: maternal behavior (undisturbed and separation-induced); anxiety by the elevated plus maze; sucrose and saccharin preference and forced swim behavior. Underlying brain areas were examined by c-fos immunocytochemistry among rest and after swim-stress. In another group of rats, vasopressin 2 receptor agonist was used peripherally to exclude secondary changes due to diabetes insipidus. Results showed that vasopressin-deficient rats spend less time licking-grooming their pups through a centrally driven mechanism. There was no difference between genotypes during the pup retrieval test. Vasopressin-deficient mothers tended to explore more the open arms of the plus maze, showed more preference for sucrose and saccharin and struggled more in the forced swim test, suggesting that they act as less depressive. Under basal conditions, vasopressin-deficient mothers had more c-fos expression in the medial preoptic area, shell of nucleus accumbens, paraventricular nucleus of the hypothalamus and amygdala, but not in other structures. In these areas the swim-stress-induced activation was smaller. In conclusion, vasopressin-deficiency resulted in maternal neglect due to a central effect and was protective against depressive-like behavior probably as a consequence of reduced activation of some stress-related brain structures. The conflicting behavioral data underscores the need for more sex specific studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Cytotoxicity and Expression of c-fos, HSP70, and GADD45/153 Proteins in Human Liver Carcinoma (HepG2 Cells Exposed to Dinitrotoluenes

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Paul B. Tchounwou

2005-08-01

Full Text Available Dinitrotoluenes (DNTs are byproducts of the explosive trinitrotoluene (TNT, and exist as a mixture of 2 to 6 isomers, with 2,4-DNT and 2,6-DNT being the most significant. The main route of human exposure at ammunition facilities is inhalation. The primary targets of DNTs toxicity are the hematopoietic system, cardiovascular system, nervous system and reproductive system. In factory workers, exposure to DNTs has been linked to many adverse health effects, including: cyanosis, vertigo, headache, metallic taste, dyspnea, weakness and lassitude, loss of appetite, nausea, and vomiting. Other symptoms including pain or parasthesia in extremities, abdominal discomfort, tremors, paralysis, chest pain, and unconsciousness have been documented. An association between DNTs exposure and increased risk of hepatocellular carcinomas and subcutaneous tumors in rats, as well as renal tumors in mice, has been established. This research was therefore designed targeting the liver to assess the cellular and molecular responses of human liver carcinoma cells following exposure to 2,4-DNT and 2,6-DNT. Cytotoxicity was evaluated using the MTT assay. Upon 48 hrs of exposure, LC50 values of 245 + 14.72μg/mL, and 300 + 5.92μg/mL were recorded for 2,6-DNT and 2,4-DNT respectively, indicating that both DNTs are moderately toxic, and 2,6-DNT is slightly more toxic to HepG2 cells than 2,4-DNT. A dose response relationship was recorded with respect to the cytotoxicity of both DNTs. Western blot analysis resulted in a significant expression (p<0.05 of the 70-kDa heat shock protein in 2,6-DNT-treated cells compared to the control cells and at the 200 μg/mL dose for 2,4-DNT. A statistically significant expression in c-fos was also observed at the 200 and 250 μg/mL treatment level for 2,4- and 2,6-DNT, respectively. However, no statistically significant expression of this protooncogene-related protein was observed at the doses of 0, 100, or 300 �

Targeting MUC1-C suppresses polycomb repressive complex 1 in multiple myeloma.

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Tagde, Ashujit; Markert, Tahireh; Rajabi, Hasan; Hiraki, Masayuki; Alam, Maroof; Bouillez, Audrey; Avigan, David; Anderson, Kenneth; Kufe, Donald

2017-09-19

The polycomb repressive complex 1 (PRC1) includes the BMI1, RING1 and RING2 proteins. BMI1 is required for survival of multiple myeloma (MM) cells. The MUC1-C oncoprotein is aberrantly expressed by MM cells, activates MYC and is also necessary for MM cell survival. The present studies show that targeting MUC1-C with (i) stable and inducible silencing and CRISPR/Cas9 editing and (ii) the pharmacologic inhibitor GO-203, which blocks MUC1-C function, downregulates BMI1, RING1 and RING2 expression. The results demonstrate that MUC1-C drives BMI1 transcription by a MYC-dependent mechanism. MUC1-C thus promotes MYC occupancy on the BMI1 promoter and thereby activates BMI1 expression. We also show that the MUC1-C→MYC pathway induces RING2 expression. Moreover, in contrast to BMI1 and RING2, we found that MUC1-C drives RING1 by an NF-κB p65-dependent mechanism. Targeting MUC1-C and thereby the suppression of these key PRC1 proteins was associated with downregulation of the PRC1 E3 ligase activity as evidenced by decreases in ubiquitylation of histone H2A. Targeting MUC1-C also resulted in activation of the PRC1-repressed tumor suppressor genes, PTEN, CDNK2A and BIM . These findings identify a heretofore unrecognized role for MUC1-C in the epigenetic regulation of MM cells.

THE MYC FAMILY OF ONCOGENES AND THEIR PRESENCE AND IMPORTANCE IN SMALL-CELL LUNG-CARCINOMA AND OTHER TUMOR TYPES

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DEVRIES, EGE; MULDER, NH

1993-01-01

The myc family of cellular oncogenes, c - myr, N - myc, encodes three highly related, cell cycle specific, nuclear phosphoproteins. All are able to transform primary rat embryo fibroblasts when cotransfected with the c - ras oncogene. Myc family genes am differentially expressed with respect to

Conserved chromosomal positions of dual domains of the ets protooncogene in cats, mice, and humans

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Watson, D.K.; McWilliams-Smith, M.J.; Kozak, C.

1986-01-01

The mammalian protooncogene homologue of the avian v-ets sequence from the E26 retrovirus consists of two sequentially distinct domains located on different chromosomes. Using somatic cell hybrid panels, the authors have mapped the mammalian homologue of the 5' v-ets-domain to chromosome 11 (ETS1) in man, to chromosome 9 (ets-1) in mouse, and to chromosome D1 (ETS1) in the domestic cat. The mammalian homologue of the 3' v-ets domain was similarly mapped to human chromosome 21 (ETS2), to mouse chromosome 16 (Ets-2), and to feline chromosome C2 (ETS2). Both protooncogenes fell in syntenic groups of homologous linked loci that were conserved among the three species. The occurrence of two distinct functional protooncogenes and their conservation of linkage positions in the three mammalian orders indicate that these two genes have been separate since before the evolutionary divergence of mammals

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

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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.

Transcriptional Inhibition of Matrix Metal loproteinase 9 (MMP-9 Activity by a c-fos/Estrogen Receptor Fusion Protein is Mediated by the Proximal AP-1 Site of the MMP-9 Promoter and Correlates with Reduced Tumor Cell Invasion

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David L. Crowe

1999-10-01

Full Text Available Tumor cell invasion of basement membranes is one of the hallmarks of malignant transformation. Tumor cells secrete proteolytic enzymes known as matrix metalloproteinases (MMPs which degrade extracellular matrix molecules. Increased expression of MMP-9 has been associated with acquisition of invasive phenotype in many tumors. However, multiple mechanisms for regulation of MMP-9 gene expression by tumor cell lines have been proposed. A number of transcription factor binding sites have been characterized in the upstream regulatory region of the MMP-9 gene, including those for AP-1. To determine how a specific AP-1 family member, c-fos, regulates MMP-9 promoter activity through these sites, we used an expression vector containing the c-fos coding region fused to the estrogen receptor (ER ligand binding domain. This construct is activated upon binding estradiol. Stable expression of this construct in ER negative squamous cell carcinoma (SCC lines produced an estradiol dependent decrease in the number of cells that migrated through a reconstituted basement membrane. This decreased invasiveness was accompanied by estradiol dependent downregulation of MMP-9 activity as determined by gelatin zymography. Estradiol also produced transcriptional downregulation of an MMP-9 promoter construct in cells transiently transfected with the c-fosER expression vector. This downregulation was mediated by the AP-1 site at —79 by in the MMP-9 promoter. We concluded that the proximal AP-1 site mediated the transcriptional downregulation of the MMP-9 promoter by a conditionally activated c-fos fusion protein.

''Normal'' tissues from humans exposed to radium contain an alteration in the c-mos locus

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Huberman, E.; Schlenker, R.A.; Hardwick, J.P.

1989-01-01

The structures of a number of human proto-oncogenes from persons with internal systemic exposure to radium were analyzed by restriction enzyme digestion and southern blotting of their DNA. Two extra c-mos Eco R1 restriction-fragment-length bands of 5.0 kb and 5.5 kb were found in tissue DNA from six of seven individuals. The extra c-mos bands were detected in DNA from many, but not all, of the tissues of the individuals exposed to radium. Our results suggest that the c-mos restriction-fragment-length alterations (RFLA) found in individuals exposed to radium were induced rather than inherited, are epigenetic in origin, and most likely result from changes in the methylation of bases surrounding the single exon of the c-mos proto-oncogene. 7 refs., 3 figs., 2 tabs

Differential effects of a selective dopamine D1-like receptor agonist on motor activity and c-fos expression in the frontal-striatal circuitry of SHR and Wistar-Kyoto rats

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Diaz Heijtz Rochellys

2006-05-01

Full Text Available Abstract Background Molecular genetic studies suggest the dopamine D1 receptor (D1R may be implicated in attention-deficit/hyperactivity disorder (ADHD. As little is known about the potential motor role of D1R in ADHD, animal models may provide important insights into this issue. Methods We investigated the effects of a full and selective D1R agonist, SKF-81297 (0.3, 3 and 10 mg/kg, on motor behaviour and expression of the plasticity-associated gene, c-fos, in habituated young adult male Spontaneously Hypertensive Rats (SHR, the most commonly used animal model of ADHD, and Wistar-Kyoto (WKY; the strain from which SHR were derived. Results SHR rats were more behaviourally active than WKY rats after injection with vehicle. The 0.3 mg/kg dose of SKF-81297 increased motor behaviour (locomotion, sifting, rearing, and sniffing in both SHR and WKY rats. Total grooming was also stimulated, but only in WKY rats. The same dose increased c-fos mRNA expression in the piriform cortex of both strains. The 3 mg/kg dose increased sifting and sniffing in both strains. Locomotion was also stimulated towards the end of the testing period. The intermediate dose decreased total rearing in both strains, and produced a significant increase in c-fos mRNA in the striatum, nucleus accumbens, olfactory tuberculum, and in the cingulate, agranular insular and piriform cortices. The 10 mg/kg dose of SKF-81297 produced a biphasic effect on locomotion, which was characterized by an initial decrease followed by later stimulation. The latter stimulatory effect was more pronounced in SHR than in WKY rats when compared to their respective vehicle-injected groups. The 10 mg/kg dose also stimulated sifting and sniffing in both strains. Both the 3 and 10 mg/kg doses had no effect on total grooming. The 10 mg/kg dose induced significantly higher levels of c-fos mRNA expression in the nucleus accumbens and adjacent cortical regions (but not striatum of SHR when compared to WKY rats

Opiate sensitization induces FosB/ΔFosB expression in prefrontal cortical, striatal and amygdala brain regions.

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Gary B Kaplan

Full Text Available Sensitization to the effects of drugs of abuse and associated stimuli contributes to drug craving, compulsive drug use, and relapse in addiction. Repeated opiate exposure produces behavioral sensitization that is hypothesized to result from neural plasticity in specific limbic, striatal and cortical systems. ΔFosB and FosB are members of the Fos family of transcription factors that are implicated in neural plasticity in addiction. This study examined the effects of intermittent morphine treatment, associated with motor sensitization, on FosB/ΔFosB levels using quantitative immunohistochemistry. Motor sensitization was tested in C57BL/6 mice that received six intermittent pre-treatments (on days 1, 3, 5, 8, 10, 12 with either subcutaneous morphine (10 mg/kg or saline followed by a challenge injection of morphine or saline on day 16. Mice receiving repeated morphine injections demonstrated significant increases in locomotor activity on days 8, 10, and 12 of treatment (vs. day 1, consistent with development of locomotor sensitization. A morphine challenge on day 16 significantly increased locomotor activity of saline pre-treated mice and produced even larger increases in motor activity in the morphine pre-treated mice, consistent with the expression of opiate sensitization. Intermittent morphine pre-treatment on these six pre-treatment days produced a significant induction of FosB/ΔFosB, measured on day 16, in multiple brain regions including prelimbic (PL and infralimbic (IL cortex, nucleus accumbens (NAc core, dorsomedial caudate-putamen (CPU, basolateral amygdala (BLA and central nucleus of the amygdala (CNA but not in a motor cortex control region. Opiate induced sensitization may develop via Fos/ΔFosB plasticity in motivational pathways (NAc, motor outputs (CPU, and associative learning (PL, IL, BLA and stress pathways (CNA.

The effects of a selective inhibitor of c-Fos/activator protein-1 on endotoxin-induced acute kidney injury in mice

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Miyazaki Hiroyuki

2012-11-01

Full Text Available Abstract Background Sepsis has been identified as the most common cause of acute kidney injury (AKI in intensive care units. Lipopolysaccharide (LPS induces the production of several proinflammatory cytokines including tumor necrosis factor (TNF-alpha, a major pathogenetic factor in septic AKI. c-Fos/activator protein (AP-1 controls the expression of these cytokines by binding directly to AP-1 motifs in the cytokine promoter regions. T-5224 is a new drug developed by computer-aided drug design that selectively inhibits c-Fos/AP-1 binding to DNA. In this study, we tested whether T-5224 has a potential inhibitory effect against LPS-induced AKI, by suppressing the TNF-alpha inflammatory response and other downstream effectors. Methods To test this hypothesis, male C57BL/6 mice at 7 weeks old were divided into three groups (control, LPS and T-5224 groups. Mice in the control group received saline intraperitoneally and polyvinylpyrrolidone solution orally. Mice in the LPS group were injected intraperitoneally with a 6 mg/kg dose of LPS and were given polyvinylpyrrolidone solution immediately after LPS injection. In the T-5224 group, mice were administered T-5224 orally at a dose of 300 mg/kg immediately after LPS injection. Serum concentrations of TNF-alpha, interleukin (IL-1beta, IL-6 and IL-10 were measured by ELISA. Moreover, the expression of intercellular adhesion molecule (ICAM-1 mRNA in kidney was examined by quantitative real-time RT-PCR. Finally, we evaluated renal histological changes. Results LPS injection induced high serum levels of TNF-alpha, IL-1beta and IL-6. However, the administration of T-5224 inhibited the LPS-induced increase in these cytokine levels. The serum levels of IL-10 in the LPS group and T-5224 group were markedly elevated compared with the control group. T-5224 also inhibited LPS-induced ICAM-1 mRNA expression. Furthermore histological studies supported an anti-inflammatory role of T-5224. Conclusions In endotoxin

BDNF restores the expression of Jun and Fos inducible transcription factors in the rat brain following repetitive electroconvulsive seizures.

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Hsieh, T F; Simler, S; Vergnes, M; Gass, P; Marescaux, C; Wiegand, S J; Zimmermann, M; Herdegen, T

1998-01-01

The expression of inducible transcription factors was studied following repetitive electroconvulsive seizures (ECS), c-Fos, c-Jun, JunB, and JunD immunoreactivities were investigated following a single (1 x ECS) or repetitive ECS evoked once per day for 4, 5, or 10 days (4 x ECS, 5 x ECS, or 10 x ECS). Animals were killed 3 or 12 h following the last ECS. Three hours after 1 x ECS, c-Fos was expressed throughout the cortex and hippocampus. After 5 x ECS and 10 x ECS, c-Fos was reexpressed in the CA4 area, but was completely absent in the other hippocampal areas and cortex. In these areas, c-Fos became only reinducible when the time lag between two ECS stimuli was 5 days. In contrast to c-Fos, intense JunB expression was inducible in the cortex and hippocampus, but not CA4 subfield, after 1 x ECS, 5 x ECS, and 10 x ECS. Repetitive ECS did not effect c-Jun and JunD expression. In a second model of systemic excitation of the brain, repetitive daily injection of kainic acid for 4 days completely failed to express c-Fos, c-Jun, and JunB after the last application whereas injection of kainic acid once per week did not alter the strong expressions compared to a single application of kainic acid. In order to study the maintenance of c-Fos expression during repetitive seizures, brain-derived neurotrophic factor (BDNF) was applied in parallel for 5 or 10 days via miniosmotic pumps and permanent cannula targeted at the hippocampus or the parietal cortex. Infusion of BDNF completely reinduced c-Fos expression during 5 x ECS or 10 x ECS in the cortex ipsilaterally to the cannula and, to a less extent, also increased the expression of c-Jun and JunB when compared to saline-treated controls. BDNF had no effect on the expression patterns in the hippocampus. ECS with or without BDNF infusion did not change the expression patterns of the constitutive transcription factors ATF-2, CREB, and SRF. These data demonstrate that various transcription factors substantially differ in their

[Effects of rhynchophylla alkaloids on vascular adventitial fibroblast apoptosis and proliferation in the thoracic aorta of spontaneously hypertensive rats].

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Dai, Guo-Hua; Sun, Jing-Chang; Qi, Dong-Mei

2012-09-01

To study the effects of rhynchophylline, isorhynchophylline, and rhynchophylla alkaloids on the vascular adventitial fibroblasts (VAF) apoptosis and proliferation in thoracic aorta of spontaneously hypertensive rats (SHR), and on the Bcl-2, Bax, c-Fos, c-Myc, laminin (LN), and fibronectin (FN). Forty 8-week old male SHR were randomly divided into five groups, i. e., the model group, the captopril group (17.5 mg/kg), the isorhynchophylline group (5.0 mg/kg), the rhynchophylline group (5.0 mg/kg), and the rhynchophylla alkaloids group (50.0 mg/kg), 8 in each group. In addition, eight 8-week old male Wistar rats were selected as the normal group. Equal volume of normal saline was given to rats in the normal group and the model group by gastrogavage. Rats in the rest groups were perfused with isovolumic medication solution (10 mL/kg), six days per week for eight successive weeks. The dosage of drugs was adjusted according to the change of body weight. The VAF apoptosis rate of the thoracic aorta was measured by Annexin V-FITC combined with PI dyeing and flow cytometry. The protein expressions of thoracic aortic Bcl-2, Bax, c-Myc, c-Fos, FN, and LN were detected by immunohistochemical assay. The adventitial transforming growth factor beta1 (TGF-beta1) mRNA expression in the thoracic aorta was detected by in situ hybridization method. Compared with the model group, the tail arterial systolic pressure decreased, the VAF apoptosis and the protein expression of Bax increased, Bcl-2, c-Fos, FN, LN, and TGF-beta1 mRNA all decreased in the thoracic aorta of SHR in each treatment group after 4-and 8-week of intervention. Rhynchophylline, isorhynchophylline, and rhynchophylla alkaloids could inhibit the protein expression of c-Myc with statistical difference (Prhynchophylla alkaloids group (P>0.05). There was statistical difference in increased VAF apoptosis and decreased protein expressions of Bcl-2, c-Myc, and LN (Prhynchophylla alkaloids group (P>0.05). Rhynchophylline

Differential Requirements for c-Myc in Chronic Hematopoietic Hyperplasia and Acute Hematopoietic Malignancies in Pten-null Mice

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Zhang, Jun; Xiao, Yechen; Guo, Yinshi; Breslin, Peter; Zhang, Shubin; Wei, Wei; Zhang, Zhou; Zhang, Jiwang

2011-01-01

Myeloproliferative disorders (MPDs), lymphoproliferative disorders (LPDs), acute T-lymphocytic or myeloid leukemia and T-lymphocytic lymphoma were developed in inducible Pten-knockout (Pten−/−) mice. The appearance of these multiple diseases in one animal model provides an opportunity to study the pathogenesis of multiple diseases simultaneously. To study whether Myc function is required for the development of these hematopoietic disorders in Pten−/− mice, we generated inducible Pten/Myc double-knockout mice (Pten−/−/Myc−/−). By comparing the hematopoietic phenotypes of these double-knockout mice with those of Pten−/− mice, we found that both sets of animals developed MPDs and LPDs. However, none of the compound-mutant mice developed acute leukemia or lymphoma. Interestingly, in contrast to the MPDs which developed in Pten−/− mice which are dominated by granulocytes, megakaryocytes predominate in the MPDs of Pten−/−/Myc−/− mice. Our study suggests that the deregulation of PI3K/Akt signaling in Pten−/− hematopoietic cells protects these cells from apoptotic cell death, resulting in chronic proliferative disorders. But due to the differential requirement for Myc in granulocyte as compared to megakaryocyte proliferation, Myc deletion converts Pten−/− MPDs from granulocyte-dominated to megakaryocyte-dominated conditions. Myc is absolutely required for the development of acute hematopoietic malignancies. PMID:21926961

RRR-alpha-tocopheryl succinate inhibits EL4 thymic lymphoma cell growth by inducing apoptosis and DNA synthesis arrest.

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Yu, W; Sanders, B G; Kline, K

1997-01-01

RRR-alpha-tocopheryl succinate (vitamin E succinate, VES) treatment of murine EL4 T lymphoma cells induced the cells to undergo apoptosis. After 48 hours of VES treatment at 20 micrograms/ml, 95% of cells were apoptotic. Evidence for the induction of apoptosis by VES treatments is based on staining of DNA for detection of chromatin condensation/fragmentation, two-color flow-cytometric analyses of DNA content, and end-labeled DNA and electrophoretic analyses for detection of DNA ladder formation. VES-treated EL4 cells were blocked in the G1 cell cycle phase; however, apoptotic cells came from all cell cycle phases. Analyses of mRNA expression of genes involved in apoptosis revealed decreased c-myc and increased bcl-2, c-fos, and c-jun mRNAs within three to six hours after treatment. Western analyses showed increased c-Jun, c-Fos, and Bcl-2 protein levels. Electrophoretic mobility shift assays showed increased AP-1 binding at 6, 12, and 24 hours after treatment and decreased c-Myc binding after 12 and 24 hours of VES treatment. Treatments of EL4 cells with VES+RRR-alpha-to-copherol reduced apoptosis without effecting DNA synthesis arrest. Treatments of EL4 cells with VES+rac-6-hydroxyl-2, 5,7,8-tetramethyl-chroman-2-carboxylic acid, butylated hydroxytoluene, or butylated hydroxyanisole had no effect on apoptosis or DNA synthesis arrest caused by VES treatments. Analyses of bcl-2, c-myc, c-jun, and c-fos mRNA levels in cells receiving VES + RRR-alpha-tocopherol treatments showed no change from cells receiving VES treatments alone, implying that these changes are correlated with VES treatments but are not causal for apoptosis. However, treatments with VES + RRR-alpha-tocopherol decreased AP-1 binding to consensus DNA oligomer, suggesting AP-1 involvement in apoptosis induced by VES treatments.

Sex Differences in Risk Preference and c-Fos Expression in Paraventricular Thalamic Nucleus of Rats During Gambling Task

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Ishii, Hironori; Onodera, Mariko; Ohara, Shinya; Tsutsui, Ken-Ichiro; Iijima, Toshio

2018-01-01

Different biological requirements between males and females may cause sex differences in decision preference when choosing between taking a risk to get a higher gain or taking a lower but sure gain. Several studies have tested this assumption in rats, however the conclusion remains controversial because the previous real-world like gambling tasks contained a learning component to track a global payoff of probabilistic outcome in addition to risk preference. Therefore, we modified a simple gambling task allowing us to exclude such learning effect, and investigated the sex difference in risk preference of rats and its neural basis. The task required water deprived rats to choose between a risky option which provided four drops of water or no reward at a 50% random chance vs. a sure option which provided predictable amount x (x = 1, 2, 3, 4). The amount and the risk were explicitly instructed so that different choice conditions could be tested trial by trial without re-learning of reward contingency. Although both sexes correctly chose the sure option with the same level of accuracy when the sure option provided the best offer (x = 4), they exhibited different choice performances when two options had the same expected value (x = 2). Males and females both preferred to take risky choices than sure choices (risk seeking), but males were more risk seeking than females. Outcome-history analysis of their choice pattern revealed that females reduced their risk preference after losing risky choices, whereas males did not. Rather, as losses continued, reaction time for subsequent risky choices got shorter in males. Given that significant sex difference features mainly emerged after negative experiences, male and female rats may evaluate an unsuccessful outcome of their decision in different manners. Furthermore, c-Fos expression in the paraventricular nucleus of the thalamus (PV) was higher in the gambling task than for the control task in males while c-fos levels did not

Myeloblastic leukemia cells conditionally blocked by myc-estrogen receptor chimeric transgenes for terminal differentiation coupled to growth arrest and apoptosis.

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Selvakumaran, M; Liebermann, D; Hoffman-Liebermann, B

1993-05-01

Conditional mutants of the myeloblastic leukemic M1 cell line, expressing the chimeric mycer transgene, have been established. It is shown that M1 mycer cells, like M1, undergo terminal differentiation coupled to growth arrest and programmed cell death (apoptosis) after treatment with the physiologic differentiation inducer interleukin-6. However, when beta-estradiol is included in the culture medium, M1 mycer cells respond to differentiation inducers like M1 myc cell lines, where the differentiation program is blocked at an intermediate stage. By manipulating the function of the mycer transgene product, it is shown that there is a 10-hour window during myeloid differentiation, from 30 to 40 hours after the addition of the differentiation inducer, when the terminal differentiation program switches from being dependent on c-myc suppression to becoming c-myc suppression independent, where activation of c-myc has no apparent effect on mature macrophages. M1 mycer cell lines provide a powerful tool to increase our understanding of the role of c-myc in normal myelopoiesis and in leukemogenesis, also providing a strategy to clone c-myc target genes.

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

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.

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.

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

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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.

Antidepressant-like effects of guanfacine and sex-specific differences in effects on c-fos immunoreactivity and paired-pulse ratio in male and female mice.

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Mineur, Yann S; Bentham, Matthew P; Zhou, Wen-Liang; Plantenga, Margreet E; McKee, Sherry A; Picciotto, Marina R

2015-10-01

The a2A-noradrenergic agonist guanfacine can decreases stress-induced smoking in female, but not male, human smokers. It is not known whether these effects are due to effects on mood regulation and/or result from nicotinic-cholinergic interactions. The objective of the study was to determine whether there are sex differences in the effect of guanfacine in tests of anxiolytic and antidepressant efficacy in mice at baseline and in a hypercholinergic model of depression induced by the acetylcholinesterase inhibitor physostigmine. The effects of guanfacine were measured in the light/dark box, tail suspension, and the forced swim test in female and male C57BL/6J mice. In parallel, electrophysiological properties were evaluated in the prefrontal cortex, a critical brain region involved in stress responses. c-fos immunoreactivity was measured in other brain regions known to regulate mood. Despite a baseline sex difference in behavior in the forced swim test (female mice were more immobile), guanfacine had similar, dose-dependent, antidepressant-like effects in mice of both sexes (optimal dose, 0.15 mg/kg). An antidepressant-like effect of guanfacine was also observed following pre-treatment with physostigmine. A sex difference in the paired-pulse ratio in the prefrontal cortex (PFC) (male, 1.4; female, 2.1) was observed at baseline that was normalized by guanfacine. Other brain areas involved in cholinergic control of depression-like behaviors, including the basolateral amygdala and lateral septum, showed sex-specific changes in c-fos expression. Guanfacine has a robust antidepressant-like effect and can reverse a depression-like state induced by increased acetylcholine (ACh) signaling. These data suggest that different brain areas are recruited in female and male mice, despite similar behavioral responses to guanfacine.

Norisoboldine suppresses osteoclast differentiation through preventing the accumulation of TRAF6-TAK1 complexes and activation of MAPKs/NF-κB/c-Fos/NFATc1 Pathways.

Directory of Open Access Journals (Sweden)

Zhi-Feng Wei

Full Text Available Norisoboldine (NOR is the main alkaloid constituent in the dry root of Lindera aggregata (Sims Kosterm. (L. strychnifolia Vill.. As reported previously, orally administered NOR displayed a robust inhibition of joint bone destruction present in both mouse collagen-induced arthritis and rat adjuvant-induced arthritis with lower efficacious doses than that required for ameliorating systemic inflammation. This attracted us to assess the effects of NOR on differentiation and function of osteoclasts, primary effector cells for inflammatory bone destruction, to get insight into its anti-rheumatoid arthritis mechanisms. Both RAW264.7 cells and mouse bone marrow-derived macrophages (BMMs were stimulated with RANKL (100 ng/mL to establish osteoclast differentiation models. ELISA, RT-PCR, gelatin zymography, western blotting, immunoprecipitation and EMSA were used to reveal related signalling pathways. NOR (10 and 30 µM, without significant cytotoxicity, showed significant reduction of the number of osteoclasts and the resorption pit areas, and it targeted osteoclast differentiation at the early stage. In conjunction with the anti-resorption effect of NOR, mRNA levels of cathepsin K and MMP-9 were decreased, and the activity of MMP-9 was attenuated. Furthermore, our mechanistic studies indicated that NOR obviously suppressed the ubiquitination of TRAF6, the accumulation of TRAF6-TAK1 complexes and the activation of ERK and p38 MAPK, and reduced the nuclear translocation of NF-κB-p65 and DNA-binding activity of NF-κB. However, NOR had little effect on expressions of TRAF6 or the phosphorylation and degradation of IκBα. Moreover, NOR markedly inhibited expressions of transcription factor NFATc1, but not c-Fos. Intriguingly, the subsequent nuclear translocations of c-Fos and NFATc1 were substantially down-regulated. Hence, we demonstrated for the first time that preventing the differentiation and function of osteoclasts at the early stage was an

Cytosolic malate dehydrogenase regulates RANKL-mediated osteoclastogenesis via AMPK/c-Fos/NFATc1 signaling

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Oh, Se Jeong [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Gu, Dong Ryun [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Jin, Su Hyun [Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Park, Keun Ha [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Lee, Seoung Hoon, E-mail: leesh2@wku.ac.kr [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Wonkwang Institute of Biomaterials and Implant, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of)

2016-06-17

Cytosolic malate dehydrogenase (malate dehydrogenase 1, MDH1) plays pivotal roles in the malate/aspartate shuttle that might modulate metabolism between the cytosol and mitochondria. In this study, we investigated the role of MDH1 in osteoclast differentiation and formation. MDH1 expression was induced by receptor activator of nuclear factor kappa-B ligand (RANKL) treatment. Knockdown of MDH1 by infection with retrovirus containing MDH1-specific shRNA (shMDH1) reduced mature osteoclast formation and bone resorption activity. Moreover, the expression of marker genes associated with osteoclast differentiation was downregulated by shMDH1 treatment, suggesting a role of MDH1 in osteoclast differentiation. In addition, intracellular ATP production was reduced following the activation of adenosine 5′ monophosphate-activated protein kinase (AMPK), a cellular energy sensor and negative regulator of RANKL-induced osteoclast differentiation, in shMDH1-infected osteoclasts compared to control cells. In addition, the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a critical transcription factor of osteoclastogenesis, was decreased with MDH1 knockdown during RANKL-mediated osteoclast differentiation. These findings provide strong evidence that MDH1 plays a critical role in osteoclast differentiation and function via modulation of the intracellular energy status, which might affect AMPK activity and NFATc1 expression.

Cytosolic malate dehydrogenase regulates RANKL-mediated osteoclastogenesis via AMPK/c-Fos/NFATc1 signaling

International Nuclear Information System (INIS)

Oh, Se Jeong; Gu, Dong Ryun; Jin, Su Hyun; Park, Keun Ha; Lee, Seoung Hoon

2016-01-01

Cytosolic malate dehydrogenase (malate dehydrogenase 1, MDH1) plays pivotal roles in the malate/aspartate shuttle that might modulate metabolism between the cytosol and mitochondria. In this study, we investigated the role of MDH1 in osteoclast differentiation and formation. MDH1 expression was induced by receptor activator of nuclear factor kappa-B ligand (RANKL) treatment. Knockdown of MDH1 by infection with retrovirus containing MDH1-specific shRNA (shMDH1) reduced mature osteoclast formation and bone resorption activity. Moreover, the expression of marker genes associated with osteoclast differentiation was downregulated by shMDH1 treatment, suggesting a role of MDH1 in osteoclast differentiation. In addition, intracellular ATP production was reduced following the activation of adenosine 5′ monophosphate-activated protein kinase (AMPK), a cellular energy sensor and negative regulator of RANKL-induced osteoclast differentiation, in shMDH1-infected osteoclasts compared to control cells. In addition, the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a critical transcription factor of osteoclastogenesis, was decreased with MDH1 knockdown during RANKL-mediated osteoclast differentiation. These findings provide strong evidence that MDH1 plays a critical role in osteoclast differentiation and function via modulation of the intracellular energy status, which might affect AMPK activity and NFATc1 expression.

Reduced basal and novelty-induced levels of activity-regulated cytoskeleton associated protein (Arc) and c-Fos mRNA in the cerebral cortex and hippocampus of APPswe/PS1ΔE9 transgenic mice

DEFF Research Database (Denmark)

Christensen, Ditte Z; Thomsen, Morten Skøtt; Mikkelsen, Jens D

2013-01-01

to a novel open field environment was compromised in different neocortical areas and the hippocampal formation in APP/PS1ΔE9 transgenic mice characterized by pronounced accumulation and deposition of beta amyloid (Aβ). Notably, the basal level of Arc and c-fos mRNA in the neocortex was significantly lower...... in APP/PS1ΔE9 compared to wild-type mice. Novelty exposure induced an increase in Arc and c-Fos mRNA in the medial prefrontal cortex (mPFC), parietal cortex, and hippocampal formation in both APP/PS1ΔE9 transgenic and wild-type mice. However, novelty-induced IEG expression did not reach the same levels...... in a transgenic mouse model of Alzheimer's disease, which is most pronounced in cortical regions, indicating that a decreased functional response in IEG expression could be partly responsible for the cognitive deficits observed in patients with Alzheimer's disease....

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...

Characterization of sur-2, a Novel Ras-Mediated Signal Transduction Component in C. elegans

National Research Council Canada - National Science Library

DesJardins, Edward

1999-01-01

... (oncogenes). A subset of proto-oncogenes comprise the RAS signal transduction pathway. Vulval development in the nematode worm Caenorhabditis elegans is controlled by a RAS signal transduction pathway. C...

Effects of 2,2',4,4'-tetrabromodiphenyl ether on neurobehavior and memory change and bcl-2, c-fos, grin1b and lingo1b gene expression in male zebrafish (Danio rerio).

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Zheng, Shukai; Liu, Caixia; Huang, Yanhong; Bao, Mian; Huang, Yuanni; Wu, Kusheng

2017-10-15

Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants in various environmental matrices and organisms and pose a threat to neural systems of organisms. However, though quite a few studies have explored the effect of PBDEs on neural behaviors such as learning and memory abilities in animals, their mechanisms are less known. We used the zebrafish model to evaluate neurotoxicity of PBDEs and observe changes in behavior and related gene expression. In behavioral testing, 50 zebrafish were divided into five groups treated with different concentrations of BDE-47. T-maze exploration was used for learning and memory testing, which was recorded by camera every 7days. After 21days, all fish were killed, and the gene expression of c-fos, bcl-2, lingo1b and grin1b in brain tissue was analyzed by RT-qPCR. The behavioral changes (latency to leave the start zone, reach the reward zone, and stay in the reward zone; accuracy in choosing the right maze arm, accumulation of freezing bouts, etc.) were related to BDE-47 concentration and had a time-effect relation with increasing exposure days, especially with 500μg/L BDE-47. BDE-47 elevated brain bcl-2, grin1b and lingo1b expression. The expression of c-fos showed an increase with 50 and 100μg/L BDE-47 exposure. The PBDE BDE-47 had a negative impact on the neurobehaviors of zebrafish and affected the expression of c-fos, bcl-2, lingo1b and grin1b in zebrafish brain tissue. Copyright © 2017 Elsevier Inc. All rights reserved.

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

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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.

Characterization of pancreatic lesions from MT-tgf alpha, Ela-myc and MT-tgf alpha/Ela-myc single and double transgenic mice.

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Liao, Dezhong Joshua; Wang, Yong; Wu, Jiusheng; Adsay, Nazmi Volkan; Grignon, David; Khanani, Fayyaz; Sarkar, Fazlul H

2006-07-05

In order to identify good animal models for investigating therapeutic and preventive strategies for pancreatic cancer, we analyzed pancreatic lesions from several transgenic models and made a series of novel findings. Female MT-tgf alpha mice of the MT100 line developed pancreatic proliferation, acinar-ductal metaplasia, multilocular cystic neoplasms, ductal adenocarcinomas and prominent fibrosis, while the lesions in males were less severe. MT-tgf alpha-ES transgenic lines of both sexes developed slowly progressing lesions that were similar to what was seen in MT100 males. In both MT100 and MT-tgf alpha-ES lines, TGF alpha transgene was expressed mainly in proliferating ductal cells. Ela-myc transgenic mice with a mixed C57BL/6, SJL and FVB genetic background developed pancreatic tumors at 2-7 months of age, and half of the tumors were ductal adenocarcinomas, similar to what was reported originally by Sandgren et al 1. However, in 20% of the mice, the tumors metastasized to the liver. MT100/Ela-myc and MT-tgf alpha-ES/Ela-myc double transgenic mice developed not only acinar carcinomas and mixed carcinomas as previously reported but also various ductal-originated lesions, including multilocular cystic neoplasms and ductal adenocarcinomas. The double transgenic tumors were more malignant and metastasized to the liver at a higher frequency (33%) compared with the Ela-myc tumors. Sequencing of the coding region of p16ink4, k-ras and Rb cDNA in small numbers of pancreatic tumors did not identify mutations. The short latency for tumor development, the variety of tumor morphology and the liver metastases seen in Ela-myc and MT-tgf alpha/Ela-myc mice make these animals good models for investigating new therapeutic and preventive strategies for pancreatic cancer.

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.

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.

Detecting and Targeting Oncogenic Myc in Breast Cancer

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2007-06-01

JPO2, with transforming activity in medulloblastoma cells. Cancer Res 2005, 65(13), 5607–5619. 58. Osthus RC, Karim B, Prescott JE, et al. The Myc...59. Prescott JE, Osthus RC, Lee LA, et al. A novel c-Myc- responsive gene, JPO1, participates in neoplastic transformation. J Biol Chem 2001, 276(51...Department of Medical Genetics and Microbiology , University of Toronto, 112 College Street, Toronto ON M5G 1L6, Canada 3 The Wistar Institute, 3601 Spruce

MYC gene delivery to adult mouse utricles stimulates proliferation of postmitotic supporting cells in vitro.

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Burns, Joseph C; Yoo, James J; Atala, Anthony; Jackson, John D

2012-01-01

The inner ears of adult humans and other mammals possess a limited capacity for regenerating sensory hair cells, which can lead to permanent auditory and vestibular deficits. During development and regeneration, undifferentiated supporting cells within inner ear sensory epithelia can self-renew and give rise to new hair cells; however, these otic progenitors become depleted postnatally. Therefore, reprogramming differentiated supporting cells into otic progenitors is a potential strategy for restoring regenerative potential to the ear. Transient expression of the induced pluripotency transcription factors, Oct3/4, Klf4, Sox2, and c-Myc reprograms fibroblasts into neural progenitors under neural-promoting culture conditions, so as a first step, we explored whether ectopic expression of these factors can reverse supporting cell quiescence in whole organ cultures of adult mouse utricles. Co-infection of utricles with adenoviral vectors separately encoding Oct3/4, Klf4, Sox2, and the degradation-resistant T58A mutant of c-Myc (c-MycT58A) triggered significant levels of supporting cell S-phase entry as assessed by continuous BrdU labeling. Of the four factors, c-MycT58A alone was both necessary and sufficient for the proliferative response. The number of BrdU-labeled cells plateaued between 5-7 days after infection, and then decreased ~60% by 3 weeks, as many cycling cells appeared to enter apoptosis. Switching to differentiation-promoting culture medium at 5 days after ectopic expression of c-MycT58A temporarily attenuated the loss of BrdU-labeled cells and accompanied a very modest but significant expansion of the sensory epithelium. A small number of the proliferating cells in these cultures labeled for the hair cell marker, myosin VIIA, suggesting they had begun differentiating towards a hair cell fate. The results indicate that ectopic expression of c-MycT58A in combination with methods for promoting cell survival and differentiation may restore regenerative

MYC gene delivery to adult mouse utricles stimulates proliferation of postmitotic supporting cells in vitro.

Directory of Open Access Journals (Sweden)

Joseph C Burns

Full Text Available The inner ears of adult humans and other mammals possess a limited capacity for regenerating sensory hair cells, which can lead to permanent auditory and vestibular deficits. During development and regeneration, undifferentiated supporting cells within inner ear sensory epithelia can self-renew and give rise to new hair cells; however, these otic progenitors become depleted postnatally. Therefore, reprogramming differentiated supporting cells into otic progenitors is a potential strategy for restoring regenerative potential to the ear. Transient expression of the induced pluripotency transcription factors, Oct3/4, Klf4, Sox2, and c-Myc reprograms fibroblasts into neural progenitors under neural-promoting culture conditions, so as a first step, we explored whether ectopic expression of these factors can reverse supporting cell quiescence in whole organ cultures of adult mouse utricles. Co-infection of utricles with adenoviral vectors separately encoding Oct3/4, Klf4, Sox2, and the degradation-resistant T58A mutant of c-Myc (c-MycT58A triggered significant levels of supporting cell S-phase entry as assessed by continuous BrdU labeling. Of the four factors, c-MycT58A alone was both necessary and sufficient for the proliferative response. The number of BrdU-labeled cells plateaued between 5-7 days after infection, and then decreased ~60% by 3 weeks, as many cycling cells appeared to enter apoptosis. Switching to differentiation-promoting culture medium at 5 days after ectopic expression of c-MycT58A temporarily attenuated the loss of BrdU-labeled cells and accompanied a very modest but significant expansion of the sensory epithelium. A small number of the proliferating cells in these cultures labeled for the hair cell marker, myosin VIIA, suggesting they had begun differentiating towards a hair cell fate. The results indicate that ectopic expression of c-MycT58A in combination with methods for promoting cell survival and differentiation may restore

Bcl-2 and N-Myc Coexpression Increases IGF-IR and Features of Malignant Growth in Neuroblastoma Cell Lines

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Rama Jasty

2001-01-01

Full Text Available The bcl-2 and c-myc oncogenes cooperate to transform multiple cell types. In the pediatric malignancy NB2, Bcl2 is highly expressed. In tumors with a poor prognosis, N-Myc, a protein homologous to c-Myc, is overexpressed as a result of gene amplification. The present study was designed to determine whether Bcl-2 cooperates with N-Myc to bestow a tumorigenic phenotype to neuroblastoma (NB cells. NB cell lines that at baseline express neither Bcl-2 nor N-Myc were stably transfected to express these gene products. In this model, we found Bcl-2 rescues N-Myc-expressing cells from apoptosis induced by serum withdrawal. Coexpression of Bcl-2 and N-Myc supports growth in low serum conditions and anchorage-independent growth in soft agar. Similarly, in vivo tumorigenic and angiogenic activity was dependent on coexpression. Our data further suggests that the mechanism underlying these changes involves the receptor for insulin growth factor type I (IGF-IR.

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.

Sexual behavior induction of c-Fos in the nucleus accumbens and amphetamine-stimulated locomotor activity are sensitized by previous sexual experience in female Syrian hamsters.

Science.gov (United States)

Bradley, K C; Meisel, R L

2001-03-15

Dopamine transmission in the nucleus accumbens can be activated by drugs, stress, or motivated behaviors, and repeated exposure to these stimuli can sensitize this dopamine response. The objectives of this study were to determine whether female sexual behavior activates nucleus accumbens neurons and whether past sexual experience cross-sensitizes neuronal responses in the nucleus accumbens to amphetamine. Using immunocytochemical labeling, c-Fos expression in different subregions (shell vs core at the rostral, middle, and caudal levels) of the nucleus accumbens was examined in female hamsters that had varying amounts of sexual experience. Female hamsters, given either 6 weeks of sexual experience or remaining sexually naive, were tested for sexual behavior by exposure to adult male hamsters. Previous sexual experience increased c-Fos labeling in the rostral and caudal levels but not in the middle levels of the nucleus accumbens. Testing for sexual behavior increased labeling in the core, but not the shell, of the nucleus accumbens. To validate that female sexual behavior can sensitize neurons in the mesolimbic dopamine pathway, the locomotor responses of sexually experienced and sexually naive females to an amphetamine injection were then compared. Amphetamine increased general locomotor activity in all females. However, sexually experienced animals responded sooner to amphetamine than did sexually naive animals. These data indicate that female sexual behavior can activate neurons in the nucleus accumbens and that sexual experience can cross-sensitize neuronal responses to amphetamine. In addition, these results provide additional evidence for functional differences between the shell and core of the nucleus accumbens and across its anteroposterior axis.

c-Fos expression is elevated in GABAergic interneurons of the gustatory cortex following novel taste learning.

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Doron, Guy; Rosenblum, Kobi

2010-07-01

Long-term sensory memories are considered to be stored in the relevant cortical region subserving the given modality. We and others have recently identified a series of molecular alterations in the gustatory cortex (GC) of the rat at different time intervals following novel taste learning. Some of these correlative modifications were also necessary for taste memory acquisition and/or consolidation. However, very little is known about the localization of these molecular modifications within the GC or about the functional activation of the GC hours after novel taste learning. Here, we hypothesize that inhibitory interneurons are activated in the GC on a scale of hours following learning and used c-Fos expression and confocal microscopy with different markers to test this hypothesis. We found that GABAergic interneurons are activated in the GC in correlation with novel taste learning. The activation was evident in the deep but not superficial layers of the dysgranular insular cortex. These results suggest that the GABAergic machinery in the deep layers of the GC participates in the processing of taste information hours after learning, and provide evidence for the involvement of a local cortical circuit not only during acquisition of new information but also during off-line processing and consolidation of taste information.

Nuclear AXIN2 represses MYC gene expression

Energy Technology Data Exchange (ETDEWEB)

Rennoll, Sherri A.; Konsavage, Wesley M.; Yochum, Gregory S., E-mail: gsy3@psu.edu

2014-01-03

Highlights: •AXIN2 localizes to cytoplasmic and nuclear compartments in colorectal cancer cells. •Nuclear AXIN2 represses the activity of Wnt-responsive luciferase reporters. •β-Catenin bridges AXIN2 to TCF transcription factors. •AXIN2 binds the MYC promoter and represses MYC gene expression. -- Abstract: The β-catenin transcriptional coactivator is the key mediator of the canonical Wnt signaling pathway. In the absence of Wnt, β-catenin associates with a cytosolic and multi-protein destruction complex where it is phosphorylated and targeted for proteasomal degradation. In the presence of Wnt, the destruction complex is inactivated and β-catenin translocates into the nucleus. In the nucleus, β-catenin binds T-cell factor (TCF) transcription factors to activate expression of c-MYC (MYC) and Axis inhibition protein 2 (AXIN2). AXIN2 is a member of the destruction complex and, thus, serves in a negative feedback loop to control Wnt/β-catenin signaling. AXIN2 is also present in the nucleus, but its function within this compartment is unknown. Here, we demonstrate that AXIN2 localizes to the nuclei of epithelial cells within normal and colonic tumor tissues as well as colorectal cancer cell lines. In the nucleus, AXIN2 represses expression of Wnt/β-catenin-responsive luciferase reporters and forms a complex with β-catenin and TCF. We demonstrate that AXIN2 co-occupies β-catenin/TCF complexes at the MYC promoter region. When constitutively localized to the nucleus, AXIN2 alters the chromatin structure at the MYC promoter and directly represses MYC gene expression. These findings suggest that nuclear AXIN2 functions as a rheostat to control MYC expression in response to Wnt/β-catenin signaling.

Nuclear AXIN2 represses MYC gene expression

International Nuclear Information System (INIS)

Rennoll, Sherri A.; Konsavage, Wesley M.; Yochum, Gregory S.

2014-01-01

Highlights: •AXIN2 localizes to cytoplasmic and nuclear compartments in colorectal cancer cells. •Nuclear AXIN2 represses the activity of Wnt-responsive luciferase reporters. •β-Catenin bridges AXIN2 to TCF transcription factors. •AXIN2 binds the MYC promoter and represses MYC gene expression. -- Abstract: The β-catenin transcriptional coactivator is the key mediator of the canonical Wnt signaling pathway. In the absence of Wnt, β-catenin associates with a cytosolic and multi-protein destruction complex where it is phosphorylated and targeted for proteasomal degradation. In the presence of Wnt, the destruction complex is inactivated and β-catenin translocates into the nucleus. In the nucleus, β-catenin binds T-cell factor (TCF) transcription factors to activate expression of c-MYC (MYC) and Axis inhibition protein 2 (AXIN2). AXIN2 is a member of the destruction complex and, thus, serves in a negative feedback loop to control Wnt/β-catenin signaling. AXIN2 is also present in the nucleus, but its function within this compartment is unknown. Here, we demonstrate that AXIN2 localizes to the nuclei of epithelial cells within normal and colonic tumor tissues as well as colorectal cancer cell lines. In the nucleus, AXIN2 represses expression of Wnt/β-catenin-responsive luciferase reporters and forms a complex with β-catenin and TCF. We demonstrate that AXIN2 co-occupies β-catenin/TCF complexes at the MYC promoter region. When constitutively localized to the nucleus, AXIN2 alters the chromatin structure at the MYC promoter and directly represses MYC gene expression. These findings suggest that nuclear AXIN2 functions as a rheostat to control MYC expression in response to Wnt/β-catenin signaling

Exogenous IFN-beta regulates the RANKL-c-Fos-IFN-beta signaling pathway in the collagen antibody-induced arthritis model.

Science.gov (United States)

Zhao, Rong; Chen, Ni-Nan; Zhou, Xiao-Wei; Miao, Ping; Hu, Chao-Ying; Qian, Liu; Yu, Qi-Wen; Zhang, Ji-Ying; Nie, Hong; Chen, Xue-hua; Li, Pu; Xu, Rong; Xiao, Lian-Bo; Zhang, Xin; Liu, Jian-Ren; Zhang, Dong-Qing

2014-12-10

Although a variety of drugs have been used to treat the symptoms of rheumatoid arthritis (RA), none of them are able to cure the disease. Interferon β (IFN-β) has pleiotropic effects on RA, but whether it can be used to treat RA remains globally controversial. Thus, in this study we tested the effects of IFN-β on RA patients and on collagen antibody-induced arthritis (CAIA) model mice. The cytokine and auto-antibody expression profiles in the serum and synovial fluid (SF) from RA patients were assessed using enzyme-linked immunosorbent assay (ELISA) and compared with the results from osteoarthritis (OA) patients. Exogenous IFN-β was administered to RA patients and CAIA model mice, and the therapeutic effects were evaluated. Endogenous IFN-β expression in the joint bones of CAIA model mice was evaluated by quantitative real-time PCR (qRT-PCR). The effects of exogenous IFN-β on CAIA model mice were assessed using a clinical scoring system, hematoxylin eosin and safranin-O with fast green counterstain histology, molybdenum target X-ray, and tartrate-resistant acid phosphatase (TRAP) staining. The RANKL-RANK signaling pathway was analyzed using qRT-PCR. The RAW 264.7 cell line was differentiated into osteoclasts with RANKL stimulation and then treated with exogenous IFN-β. The expression of inflammatory cytokines (IFN-γ, IL-17, MMP-3, and RANKL) and auto-antibodies (CII antibodies, RF-IgM, and anti-CCP/GPI) were significantly higher in RA compared with OA patients. After IFN-β intervention, some clinical symptoms in RA patients were partially alleviated, and the expression of IFN-γ, IL-17, MMP-3, and OPG) returned to normal levels. In the CAIA model, the expression of endogenous IFN-β in the joint bones was decreased. After IFN-β administration, the arthritis scores were decreased; synovial inflammation, cartilage, and bone destruction were clearly attenuated; and the expression of c-Fos and NFATc1 were reduced, while RANKL and TRAF6 expression was

Rapid and preferential activation of the c-jun gene during the mammalian UV response

International Nuclear Information System (INIS)

Devary, Y.; Gottlieb, R.A.; Lau, L.F.; Karin, M.

1991-01-01

Exposure of mammalian cells to DNA-damaging agents leads to activation of a genetic response known as the UV response. Because several previously identified UV-inducible genes contain AP-1 binding sites within their promoters, we investigated the induction of AP-1 activity by DNA-damaging agents. We found that expression of both c-jun and c-fos, which encode proteins that participate in formation of the AP-1 complex, is rapidly induced by two different DNA-damaging agents: UV and H2O2. Interestingly, the c-jun gene is far more responsive to UV than any other immediate-early gene that was examined, including c-fos. Other jun and fos genes were only marginally affected by UV or H2O2. Furthermore, UV is a much more efficient inducer of c-jun than phorbol esters, the standard inducers of c-jun expression. This preferential response of the c-jun gene is mediated by its 5' control region and requires the TPA response element, suggesting that this element also serves as an early target for the signal transduction pathway elicited by DNA damage. Both UV and H2O2 lead to a long-lasting increase in AP-1 binding activity, suggesting that AP-1 may mediate the induction of other damage-inducible genes such as human collagenase

Formaldehyde-induced histone H3 phosphorylation via JNK and the expression of proto-oncogenes

International Nuclear Information System (INIS)

Yoshida, Ikuma; Ibuki, Yuko

2014-01-01

Graphical abstract: - Highlights: • Formaldehyde modified histones. • The phosphorylation of H3S10 was increased at the promoter regions of proto-oncogenes. • The phosphorylation of H2AXS139 was attributed to FA-induced DNA damage. • The FA-induced initiation and promotion of cancer could be judged by these modifications. - Abstract: Formaldehyde (FA) is a very reactive compound that forms DNA adducts and DNA-protein crosslinks, which are known to contribute to FA-induced mutations and carcinogenesis. Post-translational modifications to histones have recently attracted attention due to their link with cancer. In the present study, we examined histone modifications following a treatment with FA. FA significantly phosphorylated histone H3 at serine 10 (H3S10), and at serine 28 (H3S28), the time-course of which was similar to the phosphorylation of H2AX at serine 139 (γ-H2AX), a marker of DNA double strand breaks. The temporal deacetylation of H3 was observed due to the reaction of FA with the lysine residues of histones. The phosphorylation mechanism was then analyzed by focusing on H3S10. The nuclear distribution of the phosphorylation of H3S10 and γ-H2AX did not overlap, and the phosphorylation of H3S10 could not be suppressed with an inhibitor of ATM/ATR, suggesting that the phosphorylation of H3S10 was independent of the DNA damage response. ERK and JNK in the MAPK pathways were phosphorylated by the treatment with FA, in which the JNK pathway was the main target for phosphorylation. The phosphorylation of H3S10 increased at the promoter regions of c-fos and c-jun, indicating a relationship between FA-induced tumor promotion activity and phosphorylation of H3S10. These results suggested that FA both initiates and promotes cancer, as judged by an analysis of histone modifications

Formaldehyde-induced histone H3 phosphorylation via JNK and the expression of proto-oncogenes

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Ikuma; Ibuki, Yuko, E-mail: ibuki@u-shizuoka-ken.ac.jp

2014-12-15

Graphical abstract: - Highlights: • Formaldehyde modified histones. • The phosphorylation of H3S10 was increased at the promoter regions of proto-oncogenes. • The phosphorylation of H2AXS139 was attributed to FA-induced DNA damage. • The FA-induced initiation and promotion of cancer could be judged by these modifications. - Abstract: Formaldehyde (FA) is a very reactive compound that forms DNA adducts and DNA-protein crosslinks, which are known to contribute to FA-induced mutations and carcinogenesis. Post-translational modifications to histones have recently attracted attention due to their link with cancer. In the present study, we examined histone modifications following a treatment with FA. FA significantly phosphorylated histone H3 at serine 10 (H3S10), and at serine 28 (H3S28), the time-course of which was similar to the phosphorylation of H2AX at serine 139 (γ-H2AX), a marker of DNA double strand breaks. The temporal deacetylation of H3 was observed due to the reaction of FA with the lysine residues of histones. The phosphorylation mechanism was then analyzed by focusing on H3S10. The nuclear distribution of the phosphorylation of H3S10 and γ-H2AX did not overlap, and the phosphorylation of H3S10 could not be suppressed with an inhibitor of ATM/ATR, suggesting that the phosphorylation of H3S10 was independent of the DNA damage response. ERK and JNK in the MAPK pathways were phosphorylated by the treatment with FA, in which the JNK pathway was the main target for phosphorylation. The phosphorylation of H3S10 increased at the promoter regions of c-fos and c-jun, indicating a relationship between FA-induced tumor promotion activity and phosphorylation of H3S10. These results suggested that FA both initiates and promotes cancer, as judged by an analysis of histone modifications.

A mechanistic study of cigarette smoke and cyclooxygenase-2 on proliferation of gastric cancer cells

International Nuclear Information System (INIS)

Shin, Vivian Y.; Liu, Edgar S.L.; Ye, Yi-Ne; Koo, Marcel W.L.; Chu, K.-M.; Cho, C.-H.

2004-01-01

Cigarette smoke has been shown to cause gastric cancer. Overexpression of cyclooxygenase-2 (COX-2) is a common characteristic in gastric malignancy. The present study aimed to explore the correlation between cigarette smoke and COX-2 in the promotion of tumorigenesis in human gastric cancer cells (AGS). We further studied the action of COX-2 on other proto-oncogenes on gastric tumor growth. Results showed that chloroform extract (CE) and ethanol extract (EE) from cigarette smoke dose-dependently stimulated gastric cancer cell proliferation, which was accompanied with an activation of ornithine decarboxylase (ODC) activity, COX-2, and c-myc expressions. Both antisense of c-myc and α-difluoromethylornithine (DFMO, specific ODC inhibitor) inhibited cell proliferation without affecting COX-2 expression in response to cigarette smoke extracts (CSE). However, selective COX-2 inhibitor (SC-236) not only blocked the proliferative activity but also the ODC activity and c-myc protein expression by CSE in gastric cancer cells. Further, supplementation of exogenous prostaglandin (PG) E 2 reversed all the inhibitory actions of SC-236. Our results underline the importance of COX-2 in the cancer-promoting effect of CSE and its modulation on its downstream growth-related genes, such as c-myc and ODC in cancer cell proliferation. These results reveal that CSE-induced gastric carcinogenesis is via the COX-2/c-myc/ODC and PGE 2 -dependent pathway. Hence, selective COX-2 inhibitor could be an effective therapeutic agent for gastric cancer in smokers

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

Science.gov (United States)

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.

New Aspects of an Old Drug – Diclofenac Targets MYC and Glucose Metabolism in Tumor Cells

Science.gov (United States)

Gottfried, Eva; Lang, Sven A.; Renner, Kathrin; Bosserhoff, Anja; Gronwald, Wolfram; Rehli, Michael; Einhell, Sabine; Gedig, Isabel; Singer, Katrin; Seilbeck, Anton; Mackensen, Andreas; Grauer, Oliver; Hau, Peter; Dettmer, Katja; Andreesen, Reinhard; Oefner, Peter J.; Kreutz, Marina

2013-01-01

Non-steroidal anti-inflammatory drugs such as diclofenac exhibit potent anticancer effects. Up to now these effects were mainly attributed to its classical role as COX-inhibitor. Here we show novel COX-independent effects of diclofenac. Diclofenac significantly diminished MYC expression and modulated glucose metabolism resulting in impaired melanoma, leukemia, and carcinoma cell line proliferation in vitro and reduced melanoma growth in vivo. In contrast, the non-selective COX inhibitor aspirin and the COX-2 specific inhibitor NS-398 had no effect on MYC expression and glucose metabolism. Diclofenac significantly decreased glucose transporter 1 (GLUT1), lactate dehydrogenase A (LDHA), and monocarboxylate transporter 1 (MCT1) gene expression in line with a decrease in glucose uptake and lactate secretion. A significant intracellular accumulation of lactate by diclofenac preceded the observed effect on gene expression, suggesting a direct inhibitory effect of diclofenac on lactate efflux. While intracellular lactate accumulation impairs cellular proliferation and gene expression, it does not inhibit MYC expression as evidenced by the lack of MYC regulation by the MCT inhibitor α-cyano-4-hydroxycinnamic acid. Finally, in a cell line with a tetracycline-regulated c-MYC gene, diclofenac decreased proliferation both in the presence and absence of c-MYC. Thus, diclofenac targets tumor cell proliferation via two mechanisms, that is inhibition of MYC and lactate transport. Based on these results, diclofenac holds potential as a clinically applicable MYC and glycolysis inhibitor supporting established tumor therapies. PMID:23874405

Brain Activation by H1 Antihistamines Challenges Conventional View of Their Mechanism of Action in Motion Sickness: A Behavioral, c-Fos and Physiological Study in Suncus murinus (House Musk Shrew

Directory of Open Access Journals (Sweden)

Longlong Tu

2017-06-01

Full Text Available Motion sickness occurs under a variety of circumstances and is common in the general population. It is usually associated with changes in gastric motility, and hypothermia, which are argued to be surrogate markers for nausea; there are also reports that respiratory function is affected. As laboratory rodents are incapable of vomiting, Suncus murinus was used to model motion sickness and to investigate changes in gastric myoelectric activity (GMA and temperature homeostasis using radiotelemetry, whilst also simultaneously investigating changes in respiratory function using whole body plethysmography. The anti-emetic potential of the highly selective histamine H1 receptor antagonists, mepyramine (brain penetrant, and cetirizine (non-brain penetrant, along with the muscarinic receptor antagonist, scopolamine, were investigated in the present study. On isolated ileal segments from Suncus murinus, both mepyramine and cetirizine non-competitively antagonized the contractile action of histamine with pKb values of 7.5 and 8.4, respectively; scopolamine competitively antagonized the contractile action of acetylcholine with pA2 of 9.5. In responding animals, motion (1 Hz, 4 cm horizontal displacement, 10 min increased the percentage of the power of bradygastria, and decreased the percentage power of normogastria whilst also causing hypothermia. Animals also exhibited an increase in respiratory rate and a reduction in tidal volume. Mepyramine (50 mg/kg, i.p. and scopolamine (10 mg/kg, i.p., but not cetirizine (10 mg/kg, i.p., significantly antagonized motion-induced emesis but did not reverse the motion-induced disruptions of GMA, or hypothermia, or effects on respiration. Burst analysis of plethysmographic-derived waveforms showed mepyramine also had increased the inter-retch+vomit frequency, and emetic episode duration. Immunohistochemistry demonstrated that motion alone did not induce c-fos expression in the brain. Paradoxically, mepyramine increased c-fos

Peptide-DNA conjugates as tailored bivalent binders of the oncoprotein c-Jun.

Science.gov (United States)

Pazos, Elena; Portela, Cecilia; Penas, Cristina; Vázquez, M Eugenio; Mascareñas, José L

2015-05-21

We describe a ds-oligonucleotide-peptide conjugate that is able to efficiently dismount preformed DNA complexes of the bZIP regions of oncoproteins c-Fos and c-Jun (AP-1), and therefore might be useful as disrupters of AP-1-mediated gene expression pathways.

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.

Targeting Self-Binding Peptides as a Novel Strategy To Regulate Protein Activity and Function: A Case Study on the Proto-oncogene Tyrosine Protein Kinase c-Src.

Science.gov (United States)

Bai, Zhengya; Hou, Shasha; Zhang, Shilei; Li, Zhongyan; Zhou, Peng

2017-04-24

Previously, we have reported a new biomolecular phenomenon spanning between protein folding and binding, termed as self-binding peptides (SBPs), where a short peptide segment in monomeric protein functions as a molecular switch by dynamically binding to/unbinding from its cognate domain in the monomer (Yang et al. J. Chem. Inf. 2015, 55, 329-342). Here, we attempt to raise the SBP as a new class of druggable targets to regulate the biological activity and function of proteins. A case study was performed on the proto-oncogene nonreceptor tyrosine kinase, c-Src, which contains two SBPs that bind separately to SH3 and SH2 domains of the kinase. State-of-the-art molecular dynamics (MD) simulations and post binding energetics analysis revealed that disrupting the kinase-intramolecular interactions of SH3 and SH2 domains with their cognate SBP ligands can result in totally different effects on the structural dynamics of c-Src kinase architecture; targeting the SH2 domain unlocks the autoinhibitory form of the kinase-this is very similar to the pTyr527 dephosphorylation that functionally activates the kinase, whereas targeting the SH3 domain can only release the domain from the tightly packed kinase but has a moderate effect on the kinase activity. Subsequently, based on the cognate SBP sequence we computationally designed a number of SH2-binding phosphopeptides using a motif grafting strategy. Fluorescence polarization (FP) assay observed that most of the designed phosphopeptides have higher binding affinity to SH2 domain as compared to the native SBP segment (K d = 53 nM). Kinase assay identified a typical dose-response relationship of phosphopeptides against kinase activation, substantiating that disruption of SH2-SBP interaction can mimic c-Src dephosphorylation and activate the kinase. Two rationally designed phosphopeptides, namely EPQpYEEIEN and EPQpYEELEN, were determined as strong binders of SH2 domain (K d = 8.3 and 15 nM, respectively) and potent activators of

MYC Immunohistochemistry to Identify MYC-Driven B-Cell Lymphomas in Clinical Practice.

Science.gov (United States)

Kluk, Michael J; Ho, Caleb; Yu, Hongbo; Chen, Benjamin J; Neuberg, Donna S; Dal Cin, Paola; Woda, Bruce A; Pinkus, Geraldine S; Rodig, Scott J

2016-02-01

Immunohistochemistry with anti-MYC antibody (MYC IHC) detects MYC protein in fixed samples of aggressive B-cell lymphomas and, according to the number of positive staining tumor nuclei, facilitates tumor subclassification, predicts underlying MYC rearrangements, and stratifies patient outcome. We aimed to determine the performance of MYC IHC in clinical practice. We reviewed MYC IHC performed on control specimens and 256 aggressive B-cell lymphomas and compared clinically reported IHC scores with experts' review. Control tissues showed less than 5% variation in daily IHC staining. Reported and expert IHC scores were well correlated (r = 0.86) with an SD of 14.2%. Reported IHC scores 30% or less and 70% or more were accurate (94.5%) compared with experts in categorizing tumors as "MYC IHC-Low" and "MYC IHC-High," respectively, but scores 40% to 60% were not (60.3%). The mean IHC score among lymphomas with MYC rearrangements was 80%, but with a large range of scores (20%-100%). There was no statistically significant association between IHC score and MYC copy number. Under optimal conditions, clinically reported MYC IHC scores are concordant with expert scores within 15%. MYC IHC does not capture all B-cell lymphomas with MYC rearrangements, however. MYC IHC and MYC fluorescence in situ hybridization are both recommended to identify MYC-driven B-cell lymphomas. © American Society for Clinical Pathology, 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Human small-cell lung cancers show amplification and expression of the N-myc gene

International Nuclear Information System (INIS)

Nau, M.M.; Brooks, B.J. Jr.; Carney, D.N.; Gazdar, A.F.; Battey, J.F.; Sausville, E.A.; Minna, J.D.

1986-01-01

The authors have found that 6 of 31 independently derived human small-cell lung cancer (SCLC) cell lines have 5- to 170-fold amplified N-myc gene sequences. The amplification is seen with probes from two separate exons of N-myc, which are homologous to either the second or the third exon of the c-myc gene. Amplified N-myc sequences were found in a tumor cell line started prior to chemotherapy, in SCLC tumor samples harvested directly from tumor metastases at autopsy, and from a resected primary lung cancer. Several N-myc-amplified tumor cell lines also exhibited N-myc hybridizing fragments not in the germ-line position. In one patient's tumor, an additional amplitifed N-myc DNA fragment was observed and this fragment was heterogeneously distributed in liver metastases. In contrast to SCLC with neuroendocrine properties, no non-small-cell lung cancer lines examined were found to have N-myc amplification. Fragments encoding two N-myc exons also detect increased amounts of a 3.1-kilobase N-myc mRNA in N-myc-amplified SCLC lines and in one cell line that does not show N-myc gene amplification. Both DNA and RNA hybridization experiments, using a 32 P-labelled restriction probe, show that in any one SCLC cell line, only one myc-related gene is amplified and expressed. They conclude that N-myc amplification is both common and potentially significant in the tumorigenesis or tumor progression of SCLC

Rat embryo cells immortalized with transfected oncogenes are transformed by gamma irradiation.

Science.gov (United States)

Endlich, B; Salavati, R; Sullivan, T; Ling, C C

1992-12-01

Cesium-137 gamma rays were used to transform rat embryo cells (REC) which were first transfected with activated c-myc or c-Ha-ras oncogenes to produce immortal cell lines (REC:myc and REC:ras). When exposed to 6 Gy of 137Cs gamma rays, some cells became morphologically transformed with focus formation frequencies of approximately 3 x 10(-4) for REC:myc and approximately 1 x 10(-4) for REC:ras, respectively. Cells isolated from foci of gamma-ray-transformed REC:myc (REC:myc:gamma) formed anchorage-independent colonies and were tumorigenic in nude mice, but foci from gamma-ray-transformed REC:ras (REC:ras:gamma) did not exhibit either of these criteria of transformation. Similar to the results with gamma irradiation, we observed a sequence-dependent phenomenon when myc and ras were transfected into REC, one at a time. REC immortalized by ras transfection were not converted to a tumorigenic phenotype by secondary transfection with myc, but REC transfected with myc were very susceptible to transformation by subsequent ras transfection. This suggests that myc-immortalized cells are more permissive to transformation via secondary treatments. In sequentially transfected REC, myc expression was high whether it was transfected first or second, whereas ras expression was highest when the ras gene was transfected secondarily into myc-containing REC. Molecular analysis of REC:ras:gamma transformants showed no alterations in structure of the transfected ras or of the endogenous ras, myc, p53, or fos genes. The expression of ras and p53 was increased in some isolates of REC:ras:gamma, but myc and fos expression were not affected. Similarly, REC:myc:gamma transformants did not demonstrate rearrangement or amplification of the transfected or the endogenous myc genes, or of the potentially cooperating Ha-, Ki-, or N-ras genes. Northern hybridization analysis revealed increased expression of N-ras in two isolates, REC:myc:gamma 33 and gamma 41, but no alterations in the expression

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

Science.gov (United States)

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.

The Melanocyte Fate in Neural Crest is Triggered by Myb Proteins through Activation of c-kit

Czech Academy of Sciences Publication Activity Database

Karafiát, Vít; Dvořáková, Marta; Pajer, Petr; Čermák, Vladimír; Dvořák, Michal

2007-01-01

Roč. 64, č. 21 (2007), s. 2975-2984 ISSN 1420-682X R&D Projects: GA MŠk(CZ) LC06061; GA ČR GA204/06/1728 Institutional research plan: CEZ:AV0Z50520514 Keywords : c-myb proto-oncogene * v-mybAMV oncogene * neural crest * cell fate determination * melanocytes * c-kit signal Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.239, year: 2007

AKT1, LKB1, and YAP1 revealed as MYC interactors with NanoLuc-based protein-fragment complementation assay. | Office of Cancer Genomics

Science.gov (United States)

The c-Myc (MYC) transcription factor is a major cancer driver and a well-validated therapeutic target. However, directly targeting MYC has been challenging. Thus, identifying proteins that interact with and regulate MYC may provide alternative strategies to inhibit its oncogenic activity. Here we report the development of a NanoLuc®-based protein-fragment complementation assay (NanoPCA) and mapping of the MYC protein interaction hub in live mammalian cells.

The Plastidial 2-C-Methyl-d-Erythritol 4-Phosphate Pathway Provides the Isoprenyl Moiety for Protein Geranylgeranylation in Tobacco BY-2 Cells[C][W

Science.gov (United States)

Gerber, Esther; Hemmerlin, Andréa; Hartmann, Michael; Heintz, Dimitri; Hartmann, Marie-Andrée; Mutterer, Jérôme; Rodríguez-Concepción, Manuel; Boronat, Albert; Van Dorsselaer, Alain; Rohmer, Michel; Crowell, Dring N.; Bach, Thomas J.

2009-01-01

Protein farnesylation and geranylgeranylation are important posttranslational modifications in eukaryotic cells. We visualized in transformed Nicotiana tabacum Bright Yellow-2 (BY-2) cells the geranylgeranylation and plasma membrane localization of GFP-BD-CVIL, which consists of green fluorescent protein (GFP) fused to the C-terminal polybasic domain (BD) and CVIL isoprenylation motif from the Oryza sativa calmodulin, CaM61. Treatment with fosmidomycin (Fos) or oxoclomazone (OC), inhibitors of the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, caused mislocalization of the protein to the nucleus, whereas treatment with mevinolin, an inhibitor of the cytosolic mevalonate pathway, did not. The nuclear localization of GFP-BD-CVIL in the presence of MEP pathway inhibitors was completely reversed by all-trans-geranylgeraniol (GGol). Furthermore, 1-deoxy-d-xylulose (DX) reversed the effects of OC, but not Fos, consistent with the hypothesis that OC blocks 1-deoxy-d-xylulose 5-phosphate synthesis, whereas Fos inhibits its conversion to 2-C-methyl-d-erythritol 4-phosphate. By contrast, GGol and DX did not rescue the nuclear mislocalization of GFP-BD-CVIL in the presence of a protein geranylgeranyltransferase type 1 inhibitor. Thus, the MEP pathway has an essential role in geranylgeranyl diphosphate (GGPP) biosynthesis and protein geranylgeranylation in BY-2 cells. GFP-BD-CVIL is a versatile tool for identifying pharmaceuticals and herbicides that interfere either with GGPP biosynthesis or with protein geranylgeranylation. PMID:19136647

DeltaFosB induces osteosclerosis and decreases adipogenesis by two independent cell-autonomous mechanisms

DEFF Research Database (Denmark)

Kveiborg, Marie; Sabatakos, George; Chiusaroli, Riccardo

2004-01-01

establishes that the skeletal phenotype is cell autonomous to the osteoblast lineage and independent of adipocyte formation. It also strongly suggests that the decreased fat phenotype of NSE-DeltaFosB mice is independent of the changes in the osteoblast lineage. In vitro, overexpression of Delta......Osteoblasts and adipocytes may develop from common bone marrow mesenchymal precursors. Transgenic mice overexpressing DeltaFosB, an AP-1 transcription factor, under the control of the neuron-specific enolase (NSE) promoter show both markedly increased bone formation and decreased adipogenesis...... of DeltaFosB on adipocyte differentiation appears to occur at early stages of stem cell commitment, affecting C/EBPbeta functions. It is concluded that the changes in osteoblast and adipocyte differentiation in DeltaFosB transgenic mice result from independent cell-autonomous mechanisms....

IRF-4 and c-Rel expression in antiviral-resistant adult T-cell leukemia/lymphoma

OpenAIRE

Ramos, Juan Carlos; Ruiz, Phillip; Ratner, Lee; Reis, Isildinha M.; Brites, Carlos; Pedroso, Celia; Byrne, Gerald E.; Toomey, Ngoc L.; Andela, Valentine; Harhaj, Edward W.; Lossos, Izidore S.; Harrington, William J.

2007-01-01

Adult T-cell leukemia/lymphoma (ATLL) is a generally fatal malignancy. Most ATLL patients fare poorly with conventional chemotherapy; however, antiviral therapy with zidovudine (AZT) and interferon alpha (IFN-α) has produced long-term clinical remissions. We studied primary ATLL tumors and identified molecular features linked to sensitivity and resistance to antiviral therapy. Enhanced expression of the proto-oncogene c-Rel was noted in 9 of 27 tumors. Resistant tumors exhibited c-Rel (6 of 1...

Radiation-induced transformation in oncogene primed C3H/10T1/2 cells; a new system for analysis of multi-step transformation in vitro

International Nuclear Information System (INIS)

Drozdoff, V.V.

1988-01-01

Several established rodent cell lines, such as C3H/10T1/2 fibroblasts, have been developed to study radiation and chemically-induced malignant transformation. Most experimental evidence has supported the idea that transformation in 10T1/2 cells involved at least two steps but that the apparent frequency of transformation depends on the density of plated cells. A new approach is presented here for studying radiation-induced transformation. An oncogene primed cell system (C3H-myc) was developed by introducing a constitutively active mouse c-myc gene into 10T1/2 cells. A primary goal was to determine if the introduction of an activated oncogene could substitute for one of the required steps in radiation-induced transformation. Results are presented that show that the expression of the exogenous myc gene significantly increased the frequency of radiation-induced transformation in these cells. Subculture experiments performed to analyze the kinetics of transformation in C3H-myc cells and reconstruction experiments allowing the effects of normal cells on radiation-induced transformants to be determined indicated that transformed cells arose very shortly after irradiation. These results support the conclusion that a radiation-induced event can complement the effect of myc in C3H-myc cells and directly result in transformation. This system thus provides an opportunity to isolate early steps in radiation-induced transformation and should facilitate the identification and analysis of these events

Dicty_cDB: Contig-U05087-1 [Dicty_cDB

Lifescience Database Archive (English)

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Understanding Selective Downregulation of c-Myc Expression through Inhibition of General Transcription Regulators in Multiple Myeloma

Science.gov (United States)

2015-06-01

We next tested whether BET bromodomain inhibition mitigated the acti- vation of proadhesion pathways in aortic endothelium, which oc- curs during the...tinuum of activity as Myc flickers on and off of weakly bound, weakly expressed promoters, but stays longer or more frequently at high output promoters

Low Dose Radiation Response Curves, Networks and Pathways in Human Lymphoblastoid Cells Exposed from 1 to 10 cGy of Acute Gamma Radiation

Energy Technology Data Exchange (ETDEWEB)

Wyrobek, A. J.; Manohar, C. F.; Nelson, D. O.; Furtado, M. R.; Bhattacharya, M. S.; Marchetti, F.; Coleman, M.A.

2011-04-18

We investigated the low dose dependency of the transcriptional response of human cells to characterize the shape and biological functions associated with the dose response curve and to identify common and conserved functions of low dose expressed genes across cells and tissues. Human lymphoblastoid (HL) cells from two unrelated individuals were exposed to graded doses of radiation spanning the range of 1-10 cGy were analyzed by transcriptome profiling, qPCR and bioinformatics, in comparison to sham irradiated samples. A set of {approx}80 genes showed consistent responses in both cell lines; these genes were associated with homeostasis mechanisms (e.g., membrane signaling, molecule transport), subcellular locations (e.g., Golgi, and endoplasmic reticulum), and involved diverse signal transduction pathways. The majority of radiation-modulated genes had plateau-like responses across 1-10 cGy, some with suggestive evidence that transcription was modulated at doses below 1 cGy. MYC, FOS and TP53 were the major network nodes of the low-dose response in HL cells. Comparison our low dose expression findings in HL cells with those of prior studies in mouse brain after whole body exposure, in human keratinocyte cultures, and in endothelial cells cultures, indicates that certain components of the low dose radiation response are broadly conserved across cell types and tissues, independent of proliferation status.

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.

Targeting Hodgkin and Reed–Sternberg Cells with an Inhibitor of Heat-Shock Protein 90: Molecular Pathways of Response and Potential Mechanisms of Resistance

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Priscilla Segges

2018-03-01

Full Text Available Classical Hodgkin lymphoma (cHL cells overexpress heat-shock protein 90 (HSP90, an important intracellular signaling hub regulating cell survival, which is emerging as a promising therapeutic target. Here, we report the antitumor effect of celastrol, an anti-inflammatory compound and a recognized HSP90 inhibitor, in Hodgkin and Reed–Sternberg cell lines. Two disparate responses were recorded. In KM-H2 cells, celastrol inhibited cell proliferation, induced G0/G1 arrest, and triggered apoptosis through the activation of caspase-3/7. Conversely, L428 cells exhibited resistance to the compound. A proteomic screening identified a total of 262 differentially expressed proteins in sensitive KM-H2 cells and revealed that celastrol’s toxicity involved the suppression of the MAPK/ERK (extracellular signal regulated kinase/mitogen activated protein kinase pathway. The apoptotic effects were preceded by a decrease in RAS (proto-oncogene protein Ras, p-ERK1/2 (phospho-extracellular signal-regulated Kinase-1/2, and c-Fos (proto-oncogene protein c-Fos protein levels, as validated by immunoblot analysis. The L428 resistant cells exhibited a marked induction of HSP27 mRNA and protein after celastrol treatment. Our results provide the first evidence that celastrol has antitumor effects in cHL cells through the suppression of the MAPK/ERK pathway. Resistance to celastrol has rarely been described, and our results suggest that in cHL it may be mediated by the upregulation of HSP27. The antitumor properties of celastrol against cHL and whether the disparate responses observed in vitro have clinical correlates deserve further research.

Involvement of AMPA receptor GluR2 and GluR3 trafficking in trigeminal spinal subnucleus caudalis and C1/C2 neurons in acute-facial inflammatory pain.

Directory of Open Access Journals (Sweden)

Makiko Miyamoto

Full Text Available To evaluate the involvement of trafficking of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR GluR2 and GluR3 subunits in an acute inflammatory orofacial pain, we analyzed nocifensive behavior, phosphorylated extracellular signal-regulated kinase (pERK and Fos expression in Vi/Vc, Vc and C1/C2 in GluR2 delta7 knock-in (KI, GluR3 delta7 KI mice and wild-type mice. We also studied Vc neuronal activity to address the hypothesis that trafficking of GluR2 and GluR3 subunits plays an important role in Vi/Vc, Vc and C1/C2 neuronal activity associated with orofacial inflammation in these mice. Late nocifensive behavior was significantly depressed in GluR2 delta7 KI and GluR3 delta7 KI mice. In addition, the number of pERK-immunoreactive (IR cells was significantly decreased bilaterally in the Vi/Vc, Vc and C1/C2 in GluR2 delta7 KI and GluR3 delta7 KI mice compared to wild-type mice at 40 min after formalin injection, and was also significantly smaller in GluR3 delta7 KI compared to GluR2 delta7 KI mice. The number of Fos protein-IR cells in the ipsilateral Vi/Vc, Vc and C1/C2 was also significantly smaller in GluR2 delta7 KI and GluR3 delta7 KI mice compared to wild-type mice 40 min after formalin injection. Nociceptive neurons functionally identified as wide dynamic range neurons in the Vc, where pERK- and Fos protein-IR cell expression was prominent, showed significantly lower spontaneous activity in GluR2 delta7 KI and GluR3 delta7 KI mice than wild-type mice following formalin injection. These findings suggest that GluR2 and GluR3 trafficking is involved in the enhancement of Vi/Vc, Vc and C1/C2 nociceptive neuronal excitabilities at 16-60 min following formalin injection, resulting in orofacial inflammatory pain.

Development of positron emission tomography probe of 64Cu-labeled anti-C-kit 12A8 Fab to measure protooncogene C-kit expression

International Nuclear Information System (INIS)

Yoshida, Chisato; Tsuji, Atsushi B.; Sudo, Hitomi; Sugyo, Aya; Sogawa, Chizuru; Inubushi, Masayuki; Uehara, Tomoya; Fukumura, Toshimitsu; Koizumi, Mitsuru; Arano, Yasushi; Saga, Tsuneo

2011-01-01

Introduction: C-kit is an important diagnostic and therapeutic target molecule for several malignancies, and c-kit-targeted drugs have been used clinically. Because abundant c-kit expression in tumors is a prerequisite for successful c-kit-targeted therapy, imaging of c-kit expression is expected to play a pivotal role in the therapeutic decision for each patient. We evaluated 64 Cu-labeled Fab of anti-c-kit antibody 12A8 as a positron emission tomography (PET) imaging probe. Methods: 111 In- or 125 I-Labeled 12A8 Fab was evaluated in vitro by cell binding, competitive inhibition and cellular internalization assays, and in vivo by biodistribution in mice bearing c-kit-expressing and -non-expressing tumors. Next, Fab fragment was labeled with the positron emitter 64 Cu and evaluated by PET. Results: Radiolabeled 12A8 Fab showed specific binding to c-kit-expressing cells with high affinity and internalized into cells after binding to c-kit on cell surface. Although tumor accumulation of [ 111 In]Fab was lower than that of [ 111 In]IgG, the faster blood clearance of [ 111 In]Fab provided higher tumor-to-blood ratio at 6 h postinjection onwards. Blood clearance of 64 Cu-labeled 12A8 Fab was slower than that of [ 111 In]Fab, but PET using [ 64 Cu]Fab clearly visualized the tumor at 6 h postinjection onwards. Conclusion: The 64 Cu-labeled 12A8 Fab could be used for c-kit-specific PET imaging and might help in selecting appropriate patients for c-kit-targeted treatments.

Influence of x-rays and UV-light on the presence of oncogene proteins in spleen cells of leukemic mice

International Nuclear Information System (INIS)

Popovic Hadzija, M.; Poljak Blazi, M.

1996-01-01

Proto-oncogenes are involved in growth, defferentiation and proliferation of normal cells, and in process of neoplastic transformation. In genome of normal cells, exist also tumor-suppressor genes, which contribute to cancer when they are inactivated. Those genes are target for carcinogenesis provoked by radiation. However, species specific genetic factors are important in determing which, if any, gene will be transformed by radiation. It is possible to presume that oncogenes are involved in the development of radioresistant phenotype of ML. Because of that, we examined the presence of c-myc protein in ML cells during the growth of ML and after the irradiation of these cells. Also, we examined the presence of tumor-suppressor protein p53, because inactivation or loss of p53 gene is in connection with transformation of cells. ML is strain specific for RFM mice. Spleen cells were tested 9 (nonterminal phase NTP) or 12 days (terminal phase TP) after inoculation of ML. Cells from NTP were also irradiate with x-rays or UV-light. C-myc protein expresse 74.98% spleen cells of healthy RFM mice. Wild type of p53 protein was detected in 60% of these cells, but mp53 was found in only 5.3% of cells. These results could be explained by the role of c-myc and p53 proteins in regulation of biologic processes. A few spleen cells of NTP expressed c-myc (15%) and mp53 (9.6%) proteins. But, in the same phase higher expressions of wp53 protein (30.5%) was found. On the other hand, the number of c-myc positive cells in TP of leukemia explanation lies in connection of c-myc protein and process of programmed cell death (apoptosis). During growth of ML the number of mp53 positive cells increased (to 47.8%), but wp53 positive cells decreased (to13.4%9). Both types of irradiation provoked strong activation of cellular c-myc gene in ML cells of NTP. We found about 95% c-myc positive cells after x-rays and 93% after UV-light

Current molecular profile of juvenile nasopharyngeal angiofibroma: First comprehensive study from India.

Science.gov (United States)

Pandey, Praveen; Mishra, Anupam; Tripathi, Ashoak Mani; Verma, Veerendra; Trivedi, Ritu; Singh, Hitendra Prakash; Kumar, Sunil; Patel, Brijesh; Singh, Vinay; Pandey, Shivani; Pandey, Amita; Mishra, Subhash Chandra

2017-03-01

An attempt is made to analyze the molecular behavior of juvenile nasopharyngeal angiofibroma (JNA). Case Series METHODS: Quantification of mRNAs expression was undertaken through real-time polymerase chain reaction in JNA (9-24) samples for VEGF-A, basic fibroblast growth factor (b-FGF), platelet-derived growth factor PDGF-A, KIT proto-oncogene receptor tyrosine kinase (c-Kit), Avian myelomatosis viral oncogene homolog (c-Myc), Harvey rat sarcoma viral oncogene homolog (H-Ras), tumor suppressor gene TP53, and androgen receptor and interleukin 6 (IL-6). The β-catenin expression was evaluated by western blot in 16 samples. Nasal polyp was taken as control. A significantly increased (P < 0.01) expression of c-myc, VEGFA, bFGF, PDGFA, c-kit, and TP53 was seen, along with enhanced expression of β-catenin. A massive enhancement of H-Ras expression was seen for the first time. Androgen receptor expression was no different, whereas IL-6 despite showing upregulation trend was not significant. The enhanced expressions of various markers suggest their potential role in JNA. Although the biological significance of c-kit, c-myc, and one of the novel markers H-Ras has yet to be defined, their significant expression may have a therapeutic importance. NA. Laryngoscope, 127:E100-E106, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

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.

N-Myc and GCN5 regulate significantly overlapping transcriptional programs in neural stem cells.

Directory of Open Access Journals (Sweden)

Verónica Martínez-Cerdeño

Full Text Available Here we examine the functions of the Myc cofactor and histone acetyltransferase, GCN5/KAT2A, in neural stem and precursor cells (NSC using a conditional knockout approach driven by nestin-cre. Mice with GCN5-deficient NSC exhibit a 25% reduction in brain mass with a microcephaly phenotype similar to that observed in nestin-cre driven knockouts of c- or N-myc. In addition, the loss of GCN5 inhibits precursor cell proliferation and reduces their populations in vivo, as does loss of N-myc. Gene expression analysis indicates that about one-sixth of genes whose expression is affected by loss of GCN5 are also affected in the same manner by loss of N-myc. These findings strongly support the notion that GCN5 protein is a key N-Myc transcriptional cofactor in NSC, but are also consistent with recruitment of GCN5 by other transcription factors and the use by N-Myc of other histone acetyltransferases. Putative N-Myc/GCN5 coregulated transcriptional pathways include cell metabolism, cell cycle, chromatin, and neuron projection morphogenesis genes. GCN5 is also required for maintenance of histone acetylation both at its putative specific target genes and at Myc targets. Thus, we have defined an important role for GCN5 in NSC and provided evidence that GCN5 is an important Myc transcriptional cofactor in vivo.

Myc contribution to γ-ray induced thymic lymphomas in mice of different genetic predispositions

International Nuclear Information System (INIS)

Sato, Toshihiro

2008-01-01

Myc gene has been suggested to be one of radiation targets in early genesis of γ ray-induced thymic lymphoma where Myc trisomy often occurs, and Myc activation results in p53 activation and apoptosis. The purpose of this study is to see the effects of radiation and mutation on Myc activation in the mouse. The lymphoma was induced by a single exposure of 3 Gy γ ray in BALB/c Bcl11b/Rit+/- and MSM p53-/- mice at 4 weeks after birth and by 4 weekly exposures of 2.5 Gy in p53+/- mouse. Genetic allele analysis for trisomy identification in the lymphoma was done by quantitative PCR using brain DNA as a control. Myc trisomy was found in the lymphoma of p53+/- mouse in 62% (23/37 animals) and of p53+/+, 66% (23/25), a similar frequency, suggesting that the target of radiation was not only the Myc activation. In addition, Myc trisomy frequency was 15% (4/27) in the lymphoma of Bcl11b+/+p53+/- and 36% (9/25), in heterozygote Bcl11b+/-. This finding suggested that the functional failure of Bcl11b reduced the contribution of Myc trisomy to the genesis. It was concluded that contribution of Myc trisomy to genesis of the lymphoma was dependent on genetic predisposition, and Myc-activated-, Bcl11b/Rit1-signal pathways played a parallel role in the genesis. (R.T.)

MYC translocation-negative classical Burkitt lymphoma cases: an alternative pathogenetic mechanism involving miRNA deregulation

DEFF Research Database (Denmark)

Leucci, E; Cocco, M; Onnis, A

2008-01-01

at the standardization of FISH procedures in lymphoma diagnosis, we found that five cases out of 35 classic endemic BLs were negative for MYC translocations by using a split-signal as well as a dual-fusion probe. Here we investigated the expression pattern of miRNAs predicted to target c-Myc, in BL cases, to clarify...... whether alternative pathogenetic mechanisms may be responsible for lymphomagenesis in cases lacking the MYC translocation. miRNAs are a class of small RNAs that are able to regulate gene expression at the post-transcriptional level. Several studies have reported their involvement in cancer...

Expression of the Pokemon proto-oncogene in nasopharyngeal carcinoma cell lines and tissues.

Science.gov (United States)

Jiao, Wei; Liu, Fei; Tang, Feng-Zhu; Lan, Jiao; Xiao, Rui-Ping; Chen, Xing-Zhou; Ye, Hui-Lan; Cai, Yong-Lin

2013-01-01

To study the differentiated expression of the proto-oncogene Pokemon in nasopharyngeal carcinoma (NPC) cell lines and tissues, mRNA and protein expression levels of CNE1, CNE2, CNE3 and C666-1 were detected separately by reverse transcription polymerase chain reaction (RT-PCR), real-time PCR and Western-blotting. The immortalized nasopharyngeal epithelial cell line NP69 was used as a control. The Pokemon protein expression level in biopsy specimens from chronic rhinitis patients and undifferentiated non keratinizing NPC patients was determined by Western-blotting and arranged from high to low: C666-1>CNE1>CNE2> CNE3>NP69. The Pokemon mRNA expression level was also arranged from high to low: CNE1>CNE2>NP69>C666-1>CNE3. Pokemon expression of NP69 and C666-1 obviously varied from mRNA to protein. The Pokemon protein level of NPC biopsy specimens was obviously higher than in chronic rhinitis. The data suggest that high Pokemon protein expression is closely associated with undifferentiated non-keratinizing NPC and may provide useful information for NPC molecular target therapy.

[Food-procuring stereotype movements is accompanied by changes of c-Fos gene expression in the amygdala and modulation of heart rate in rats].

Science.gov (United States)

Dovgan', O V; Vlasenko, O V; Buzyka, T V; Maĭs'kyĭ, V O; Piliavs'kyĭ, O I; Maznychenko, A V

2012-01-01

The distribution of Fos-immunoreactive (Fos-ir) and NADPH Diaphorase reactive (NADPH-dr-) neurons in the different subnuclei of amygdala and insular cortex (on the level -2,12 to -3,14 mm from bregma), and the associated changes of heart rate (HR) in intact, food-deprivated and executed food-procuring movements of rats were studied. In comparison with other groups of animals, the mean number of the Fos-ir neurons in the central nucleus of amygdala (Ce) and the insular cortex (GI/DI) at all studied levels was significantly greater in the executed food-procuring movements in rats. The main focus of localization of the Fos-ir neurons was found in lateral part of the Ce (58.5 +/- 1.9 units in 40-microm-thick section) at the level -2.56 mm. The mean number of Fos-ir neurons was significantly greater also in the lateral and capsular parts of the Ce. The mean number of Fos-ir neurons in the GI/DI was 165.5 +/- 3.2 cells in section. The number and density of NADPH-d reactive neurons was not significantly different in the brain structures of all animal groups studied. The double stained neurons (Fos-ir + NADPH-dr) were registered in medial, basolateral, anterior cortical amygdaloid nuclei and substantia innominata (SI) in rats after realization food-procuring movements. It was found that realization of food-procuring movements by the forelimb during repeated sessions was accompanied with the gradual decline of mean values of the HR (from 5% to 12% of control level) with subsequent renewal of them to the initial values (tonic component). The analysis of dynamics of the HR changes during realization of separate purposeful motion has shown the transient period of the HR suppression (500 ms), which coincided with the terminal phase of grasping of food pellet (phasic component). We suggest that the revealed focuses of localization of Fos-ir neurons in the lateral and medial subregions of amigdaloid Ce and also GI/DI, and SI testified that these structures of brain are involved

Hepatitis C virus core protein targets 4E-BP1 expression and phosphorylation and potentiates Myc-induced liver carcinogenesis in transgenic mice.

Science.gov (United States)

Abdallah, Cosette; Lejamtel, Charlène; Benzoubir, Nassima; Battaglia, Serena; Sidahmed-Adrar, Nazha; Desterke, Christophe; Lemasson, Matthieu; Rosenberg, Arielle R; Samuel, Didier; Bréchot, Christian; Pflieger, Delphine; Le Naour, François; Bourgeade, Marie-Françoise

2017-08-22

Hepatitis C virus (HCV) is a leading cause of liver diseases including the development of hepatocellular carcinoma (HCC). Particularly, core protein has been involved in HCV-related liver pathologies. However, the impact of HCV core on signaling pathways supporting the genesis of HCC remains largely elusive. To decipher the host cell signaling pathways involved in the oncogenic potential of HCV core, a global quantitative phosphoproteomic approach was carried out. This study shed light on novel differentially phosphorylated proteins, in particular several components involved in translation. Among the eukaryotic initiation factors that govern the translational machinery, 4E-BP1 represents a master regulator of protein synthesis that is associated with the development and progression of cancers due to its ability to increase protein expression of oncogenic pathways. Enhanced levels of 4E-BP1 in non-modified and phosphorylated forms were validated in human hepatoma cells and in mouse primary hepatocytes expressing HCV core, in the livers of HCV core transgenic mice as well as in HCV-infected human primary hepatocytes. The contribution of HCV core in carcinogenesis and the status of 4E-BP1 expression and phosphorylation were studied in HCV core/Myc double transgenic mice. HCV core increased the levels of 4E-BP1 expression and phosphorylation and significantly accelerated the onset of Myc-induced tumorigenesis in these double transgenic mice. These results reveal a novel function of HCV core in liver carcinogenesis potentiation. They position 4E-BP1 as a tumor-specific target of HCV core and support the involvement of the 4E-BP1/eIF4E axis in hepatocarcinogenesis.

Mapping of olfactory memory circuits: region-specific c-fos activation after odor-reward associative learning or after its retrieval.

Science.gov (United States)

Tronel, Sophie; Sara, Susan J

2002-01-01

Although there is growing knowledge about intracellular mechanisms underlying neuronal plasticity and memory consolidation and reconsolidation after retrieval, information concerning the interaction among brain areas during formation and retrieval of memory is relatively sparse and fragmented. Addressing this question requires simultaneous monitoring of activity in multiple brain regions during learning, the post-acquisition consolidation period, and retrieval and subsequent reconsolidation. Immunoreaction to the immediate early gene c-fos is a powerful tool to mark neuronal activation of specific populations of neurons. Using this method, we are able to report, for the first time, post-training activation of a network of closely related brain regions, particularly in the frontal cortex and the basolateral amygdala (BLA), that is specific to the learning of an odor-reward association. On the other hand, retrieval of a well-established associative memory trace does not seem to differentially activate the same regions. The amygdala, in particular, is not engaged after retrieval, whereas the lateral habenula (LHab) shows strong activation that is restricted to animals having previously learned the association. Although intracellular mechanisms may be similar during consolidation and reconsolidation, this study indicates that different brain circuits are involved in the two processes, at least with respect to a rapidly learned olfactory task.

Role of progesterone and estrogen in the preparation of the uterus and induction of implantation in the mouse

Energy Technology Data Exchange (ETDEWEB)

Huet-Hudson, Y.M.

1989-01-01

The implantation of the embryo into the uterine wall and subsequent decidualization of the uterine endometrium requires ovarian progesterone and estrogen. Prerequisites for implantation include (1) the preparation of the uterus for embryo implantation and (2) increase stromal capillary permeability at the site of embryo attachment. During the first three days of pregnancy, epithelial cells undergo proliferation, death and differentiation, in response to preovaluatory estrogen. These events occur in stromal cells in response to progesterone on days 4 and 5. The mechanism by which the steroid hormones modulate their functions and how estrogen initiates implantation in a progesterone-primed (P{sub 4}) uterus in not clearly understood. The author shows that 24h of P{sub 4}-priming is adequate for induction of implantation in the mouse. In addition, following this initial exposure of the uterus to P{sub 4} a long lasting effect is induced i.e. 24h of priming is no longer required for the induction of implantation. The uterine cell proliferation and differentiation that occurs in response to steroid hormones could be through their modulation of the expression of proto-oncogenes and growth factors. Results show that the proto-oncogene, c-myc and the growth factor, EGF are expressed in a cell-type specific manner in the uterus and are regulated by P{sub 4} and estrogen in a spatial and temporal manner during early pregnancy. It is apparent that c-myc protein in epithelia is primarily regulated by estrogen, while in the stroma by P{sub 4}. {sup 3}H-thymidine incorporation in specific uterine cell-types correlated with expression of the c-myc protein. On the other hand, EGF is always localized to the epithelia and is primarily regulated by estrogen.

Myc-nick: a cytoplasmic cleavage product of Myc that promotes alpha-tubulin acetylation and cell differentiation.

Science.gov (United States)

Conacci-Sorrell, Maralice; Ngouenet, Celine; Eisenman, Robert N

2010-08-06

The Myc oncoprotein family comprises transcription factors that control multiple cellular functions and are widely involved in oncogenesis. Here we report the identification of Myc-nick, a cytoplasmic form of Myc generated by calpain-dependent proteolysis at lysine 298 of full-length Myc. Myc-nick retains conserved Myc box regions but lacks nuclear localization signals and the bHLHZ domain essential for heterodimerization with Max and DNA binding. Myc-nick induces alpha-tubulin acetylation and altered cell morphology by recruiting histone acetyltransferase GCN5 to microtubules. During muscle differentiation, while the levels of full-length Myc diminish, Myc-nick and acetylated alpha-tubulin levels are increased. Ectopic expression of Myc-nick accelerates myoblast fusion, triggers the expression of myogenic markers, and permits Myc-deficient fibroblasts to transdifferentiate in response to MyoD. We propose that the cleavage of Myc by calpain abrogates the transcriptional inhibition of differentiation by full-length Myc and generates Myc-nick, a driver of cytoplasmic reorganization and differentiation. Copyright 2010 Elsevier Inc. All rights reserved.

Myc Decoy Oligodeoxynucleotide Inhibits Growth and Modulates Differentiation of Mouse Embryonic Stem Cells as a Model of Cancer Stem Cells.

Science.gov (United States)

Johari, Behrooz; Ebrahimi-Rad, Mina; Maghsood, Faezeh; Lotfinia, Majid; Saltanatpouri, Zohreh; Teimoori-Toolabi, Ladan; Sharifzadeh, Zahra; Karimipoor, Morteza; Kadivar, Mehdi

2017-01-01

Myc (c-Myc) alone activates the embryonic stem cell-like transcriptional module in both normal and transformed cells. Its dysregulation might lead to increased cancer stem cells (CSCs) population in some tumor cells. In order to investigate the potential of Myc decoy oligodeoxynucleotides for differentiation therapy, mouse embryonic stem cells (mESCs) were used in this study as a model of CSCs. To our best of knowledge this is the first report outlining the application of Myc decoy in transcription factor decoy "TFD" strategy for inducing differentiation in mESCs. A 20-mer double-stranded Myc transcription factor decoy and scrambled oligodeoxynucleotides (ODNs) were designed, analyzed by electrophoretic mobility shift (EMSA) assay and transfected into the mESCs under 2 inhibitors (2i) condition. Further investigations were carried out using fluorescence and confocal microscopy, cell proliferation and apoptosis analysis, alkaline phosphatase and embryoid body formation assay, real-time PCR and western blotting. EMSA data showed that Myc decoy ODNs bound specifically to c-Myc protein. They were found to be localized in both cytoplasm and nucleus of mESCs. Our results revealed the potential capability of Myc decoy ODNs to decrease cell viability by (16.1±2%), to increase the number of cells arrested in G0/G1 phases and apoptosis by (14.2±3.1%) and (12.1±3.2%), respectively regarding the controls. Myc decoy could also modulate differentiation in mESCs despite the presence of 2i/LIF in our medium the presence of 2i/LIF in our medium. The optimized Myc decoy ODNs approach might be considered as a promising alternative strategy for differentiation therapy investigations. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

miR-218 is involved in the negative regulation of osteoclastogenesis and bone resorption by partial suppression of p38MAPK-c-Fos-NFATc1 signaling: Potential role for osteopenic diseases.

Science.gov (United States)

Qu, Bo; Xia, Xun; Yan, Ming; Gong, Kai; Deng, Shaolin; Huang, Gang; Ma, Zehui; Pan, Xianming

2015-10-15

The increased osteoclastic activity accounts for pathological bone loss in diseases including osteoporosis. MicroRNAs are widely accepted to be involved in the regulation of osteopenic diseases. Recently, the low expression of miR-218 was demonstrated in CD14(+) peripheral blood mononuclear cells (PBMCs) from patients with postmenopausal osteoporosis. However, its role and the underlying mechanism in osteoporosis are still undefined. Here, an obvious decrease in miR-218 expression was observed during osteoclastogenesis under receptor activator of nuclear factor κB ligand (RANKL) stimulation, in both osteoclast precursors of bone marrow macrophages (BMMs) and RAW 264.7. Further analysis confirmed that overexpression of miR-218 obviously attenuated the formation of multinuclear mature osteoclasts, concomitant with the decrease in Trap and Cathepsin K levels, both the master regulators of osteoclastogenesis. Moreover, miR-218 up-regulation dramatically inhibited osteoclast precursor migration, actin ring formation and bone resorption. Mechanism assay demonstrated that miR-218 overexpression attenuated the expression of p38MAPK, c-Fos and NFATc1 signaling molecules. Following preconditioning with P79350, an agonist of p38MAPK, the inhibitor effect of miR-218 on osteoclastogenesis and bone-resorbing activity was strikingly ameliorated. Together, this study revealed a crucial role of miR-218 as a negative regulator for osteoclastogenesis and bone resorption by suppressing the p38MAPK-c-Fos-NFATc1 pathway. Accordingly, this research will provide a promising therapeutic agent against osteopenic diseases including osteoporosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Regulation of gene expression in mammalian cells following ionizing radiation

International Nuclear Information System (INIS)

Boothman, D.A.; Lee, S.W

1991-01-01

Mammalian cells use a variety of mechanisms to control the expression of new gene transcrips elicited in response to ionizing radiation. Damage-induced proteins have been found which contain DNA binding sites located within the promoter regions of SV40 and human thymidine kinase genes. DNA binding proteins as well as proteins which bind to specific DNA lesions (e.g., XIP bp 175 binds specifically to X-ray-damaged DNA) may play a role in the initial recognition of DNA damage and may initiate DNA repair processes, along with new transcription. Mammalian gene expression after DNA damage is also regulated via the stabilization of preexisting mRNA transcripts. Stabilized mRNA transcripts are translated into protein products not previously present in the cell due to undefined posttranscriptional modifications. Thus far, the only example of mRNA stabilization following X-irradiation is the immediate induction of tissue-type plasminogen activator. Mammalian cells synthesize new mRNA transcripts indirect response to DNA damage. Using cDNA cloning, Northern RNA blotting and nuclear run-on techniques, the levels of a variety of known and previously unknown genes dramatically increase following X-irradiation. These genes/proteins now include; a) DNA binding transcripts factors, such as the UV-responsive element binding factors, ionizing radiation-induced DNA-binding proteins, and XIP bP 175; b) proto-oncogenes, such as c-fos, c-jun, and c-myc; c) several growth-related genes, (e.g., the gadd genes, protein kinase C, IL-1, and thymidine kinase); and d) a variety of other genes, including proteases, tumor necrosis factor-alpha, and DT diaphorase. Mammalian cells respond to X-irradiation by eliciting a very complex series of events resulting in the appearance of new genes and proteins. These gene products may affect DNA repair, adaptive responses, apoptosis, SOS-type mutagenic response, and/or carcinogenesis. (J.P.N.)

Increased Fos expression among midbrain dopaminergic cell groups during birdsong tutoring.

Science.gov (United States)

Nordeen, E J; Holtzman, D A; Nordeen, K W

2009-08-01

During avian vocal learning, birds memorize conspecific song patterns and then use auditory feedback to match their vocal output to this acquired template. Some models of song learning posit that during tutoring, conspecific visual, social and/or auditory cues activate neuromodulatory systems that encourage acquisition of the tutor's song and attach incentive value to that specific acoustic pattern. This hypothesis predicts that stimuli experienced during social tutoring activate cell populations capable of signaling reward. Using immunocytochemistry for the protein product of the immediate early gene c-Fos, we found that brief exposure of juvenile male zebra finches to a live familiar male tutor increased the density of Fos+ cells within two brain regions implicated in reward processing: the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). This activation of Fos appears to involve both dopaminergic and non-dopaminergic VTA/SNc neurons. Intriguingly, a familiar tutor was more effective than a novel tutor in stimulating Fos expression within these regions. In the periaqueductal gray, a dopamine-enriched cell population that has been implicated in emotional processing, Fos labeling also was increased after tutoring, with a familiar tutor again being more effective than a novel conspecific. As several neural regions implicated in song acquisition receive strong dopaminergic projections from these midbrain nuclei, their activation in conjunction with hearing the tutor's song could help to establish sensory representations that later guide motor sequence learning.

MYC association with cancer risk and a new model of MYC-mediated repression.

Science.gov (United States)

Cole, Michael D

2014-07-01

MYC is one of the most frequently mutated and overexpressed genes in human cancer but the regulation of MYC expression and the ability of MYC protein to repress cellular genes (including itself) have remained mysterious. Recent genome-wide association studies show that many genetic polymorphisms associated with disease risk map to distal regulatory elements that regulate the MYC promoter through large chromatin loops. Cancer risk-associated single-nucleotide polymorphisms (SNPs) contain more potent enhancer activity, promoting higher MYC levels and a greater risk of disease. The MYC promoter is also subject to complex regulatory circuits and limits its own expression by a feedback loop. A model for MYC autoregulation is discussed which involves a signaling pathway between the PTEN (phosphatase and tensin homolog) tumor suppressor and repressive histone modifications laid down by the EZH2 methyltransferase. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Modulation of expression of genes encoding nuclear proteins following exposure to JANUS neutrons or γ-rays

International Nuclear Information System (INIS)

Woloschak, G.E.; Chang-Liu, Chin-Mei

1994-01-01

Previous work has shown that exposure of cells to ionizing radiations causes modulation of a variety of genes, including those encoding c-fos, interleukin-1, tumor necrosis factor, cytoskeletal elements, and many more. The experiments reported herein were designed to examine the effects of either JANUS neutron or γ-ray exposure on expression of genes encoding nucleus-associated proteins (H4-histone, c-jun, c-myc, Rb, and p53). Cycling Syrian hamster embryo cells were irradiated with varying doses and dose rates of either JANUS fission-spectrum neutrons or γ-rays; after incubation of the cell cultures for 1 h following radiation exposure, mRNA was harvested and analyzed by Northern blot. Results revealed induction of transcripts for c-jun, H4-histone, and Rb following γ-ray but not following neutron exposure. Interestingly, expression of c-myc was repressed following γ-ray but not following neutron exposure. Radiations at different doses and dose rates were compared for each of the genes studied

Targeted repression of AXIN2 and MYC gene expression using designer TALEs

International Nuclear Information System (INIS)

Rennoll, Sherri A.; Scott, Samantha A.; Yochum, Gregory S.

2014-01-01

Highlights: • We designed TALE–SID fusion proteins to target AXIN2 and MYC. • TALE–SIDs bound the chromosomal AXIN2 and MYC genes and repressed their expression. • TALE–SIDs repress β-catenin S45F -dependent AXIN2 and MYC transcription. - Abstract: Designer TALEs (dTALEs) are chimeric transcription factors that can be engineered to regulate gene expression in mammalian cells. Whether dTALEs can block gene transcription downstream of signal transduction cascades, however, has yet to be fully explored. Here we tested whether dTALEs can be used to target genes whose expression is controlled by Wnt/β-catenin signaling. TALE DNA binding domains were engineered to recognize sequences adjacent to Wnt responsive enhancer elements (WREs) that control expression of axis inhibition protein 2 (AXIN2) and c-MYC (MYC). These custom DNA binding domains were linked to the mSin3A interaction domain (SID) to generate TALE–SID chimeric repressors. The TALE–SIDs repressed luciferase reporter activity, bound their genomic target sites, and repressed AXIN2 and MYC expression in HEK293 cells. We generated a novel HEK293 cell line to determine whether the TALE–SIDs could function downstream of oncogenic Wnt/β-catenin signaling. Treating these cells with doxycycline and tamoxifen stimulates nuclear accumulation of a stabilized form of β-catenin found in a subset of colorectal cancers. The TALE–SIDs repressed AXIN2 and MYC expression in these cells, which suggests that dTALEs could offer an effective therapeutic strategy for the treatment of colorectal cancer

Targeted repression of AXIN2 and MYC gene expression using designer TALEs

Energy Technology Data Exchange (ETDEWEB)

Rennoll, Sherri A.; Scott, Samantha A.; Yochum, Gregory S., E-mail: gsy3@psu.edu

2014-04-18

Highlights: • We designed TALE–SID fusion proteins to target AXIN2 and MYC. • TALE–SIDs bound the chromosomal AXIN2 and MYC genes and repressed their expression. • TALE–SIDs repress β-catenin{sup S45F}-dependent AXIN2 and MYC transcription. - Abstract: Designer TALEs (dTALEs) are chimeric transcription factors that can be engineered to regulate gene expression in mammalian cells. Whether dTALEs can block gene transcription downstream of signal transduction cascades, however, has yet to be fully explored. Here we tested whether dTALEs can be used to target genes whose expression is controlled by Wnt/β-catenin signaling. TALE DNA binding domains were engineered to recognize sequences adjacent to Wnt responsive enhancer elements (WREs) that control expression of axis inhibition protein 2 (AXIN2) and c-MYC (MYC). These custom DNA binding domains were linked to the mSin3A interaction domain (SID) to generate TALE–SID chimeric repressors. The TALE–SIDs repressed luciferase reporter activity, bound their genomic target sites, and repressed AXIN2 and MYC expression in HEK293 cells. We generated a novel HEK293 cell line to determine whether the TALE–SIDs could function downstream of oncogenic Wnt/β-catenin signaling. Treating these cells with doxycycline and tamoxifen stimulates nuclear accumulation of a stabilized form of β-catenin found in a subset of colorectal cancers. The TALE–SIDs repressed AXIN2 and MYC expression in these cells, which suggests that dTALEs could offer an effective therapeutic strategy for the treatment of colorectal cancer.

An oncogenic axis of STAT-mediated BATF3 upregulation causing MYC activity in classical Hodgkin lymphoma and anaplastic large cell lymphoma.

Science.gov (United States)

Lollies, A; Hartmann, S; Schneider, M; Bracht, T; Weiß, A L; Arnolds, J; Klein-Hitpass, L; Sitek, B; Hansmann, M-L; Küppers, R; Weniger, M A

2018-01-01

Classical Hodgkin lymphoma (cHL) and anaplastic large cell lymphoma (ALCL) feature high expression of activator protein-1 (AP-1) transcription factors, which regulate various physiological processes but also promote lymphomagenesis. The AP-1 factor basic leucine zipper transcription factor, ATF-like 3 (BATF3), is highly transcribed in cHL and ALCL; however, its functional importance in lymphomagenesis is unknown. Here we show that proto-typical CD30 + lymphomas, namely cHL (21/30) and primary mediastinal B-cell lymphoma (8/9), but also CD30 + diffuse large B-cell lymphoma (15/20) frequently express BATF3 protein. Mass spectrometry and co-immunoprecipitation established interactions of BATF3 with JUN and JUNB in cHL and ALCL lines. BATF3 knockdown using short hairpin RNAs was toxic for cHL and ALCL lines, reducing their proliferation and survival. We identified MYC as a critical BATF3 target and confirmed binding of BATF3 to the MYC promoter. JAK/STAT signaling regulated BATF3 expression, as chemical JAK2 inhibition reduced and interleukin 13 stimulation induced BATF3 expression in cHL lines. Chromatin immunoprecipitation substantiated a direct regulation of BATF3 by STAT proteins in cHL and ALCL lines. In conclusion, we identified STAT-mediated BATF3 expression that is essential for lymphoma cell survival and promoted MYC activity in cHL and ALCL, hence we recognized a new oncogenic axis in these lymphomas.

Serine 62-Phosphorylated MYC Associates with Nuclear Lamins and Its Regulation by CIP2A Is Essential for Regenerative Proliferation

Directory of Open Access Journals (Sweden)

Kevin Myant

2015-08-01

Full Text Available An understanding of the mechanisms determining MYC’s transcriptional and proliferation-promoting activities in vivo could facilitate approaches for MYC targeting. However, post-translational mechanisms that control MYC function in vivo are poorly understood. Here, we demonstrate that MYC phosphorylation at serine 62 enhances MYC accumulation on Lamin A/C-associated nuclear structures and that the protein phosphatase 2A (PP2A inhibitor protein CIP2A is required for this process. CIP2A is also critical for serum-induced MYC phosphorylation and for MYC-elicited proliferation induction in vitro. Complementary transgenic approaches and an intestinal regeneration model further demonstrated the in vivo importance of CIP2A and serine 62 phosphorylation for MYC activity upon DNA damage. However, targeting of CIP2A did not influence the normal function of intestinal crypt cells. These data underline the importance of nuclear organization in the regulation of MYC phosphorylation, leading to an in vivo demonstration of a strategy for inhibiting MYC activity without detrimental physiological effects.