Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Induction of phase 2 detoxification enzymes by phenolic antioxidants can account for prevention of tumor initiation but cannot explain why these compounds inhibit tumor promotion. Phase 2 genes are induced through an antioxidant response element (ARE). Although the ARE resembles an AP-1 binding site, we show that the major ARE binding and activating protein is not AP-1. Interestingly, AP-1 DNA binding activity was induced by the phenolic antioxidant tert-butylhydroquinone (BHQ), but the induction of AP-1 transcriptional activity by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) was inhibited by this compound. BHQ induced expression of c-jun, junB, fra-1, and fra-2, which encode AP-1 components, but was a poor inducer of c-fos and had no effect on fosB. Like c-Fos and FosB, the Fra proteins heterodimerize with Jun proteins to form stable AP-1 complexes. However, Fra-containing AP-1 complexes have low transactivation potential. Furthermore, Fra-1 repressed AP-1 activity induced by either TPA or expression of c-Jun and c-Fos. We therefore conclude that inhibitory AP-1 complexes composed of Jun-Fra heterodimers, induced by BHQ, antagonize the transcriptional effects of the tumor promoter TPA, which are mediated by Jun-Fos heterodimers. Since AP-1 is an important mediator of tumor promoter action, these findings may explain the anti-tumor-promoting activity of phenolic antioxidants.
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PMID:Antitumor promotion by phenolic antioxidants: inhibition of AP-1 activity through induction of Fra expression. 776 34

Curcumin (diferuloylmethane), the naturally occurring yellow pigment in turmeric and curry, is isolated from the rhizomes of the plant Curcuma longa Linn. Curcumin inhibits tumorigenesis during both initiation and promotion (post-initiation) periods in several experimental animal models. Topical application of curcumin inhibits benzo[a]pyrene (B[a]P)-mediated formation of DNA-B[a]P adducts in the epidermis. It also reduces 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced increases in skin inflammation, epidermal DNA synthesis, ornithine decarboxylase (ODC) mRNA level, ODC activity, hyperplasia, formation of c-Fos, and c-Jun proteins, hydrogen peroxide, and the oxidized DNA base 5-hydroxymethyl-2'-deoxyuridine (HmdU). Topical application of curcumin inhibits TPA-induced increases in the percent of epidermal cells in synthetic (S) phase of the cell cycle. Curcumin is a strong inhibitor of arachidonic acid-induced edema of mouse ears in vivo and epidermal cyclooxygenase and lipoxygenase activities in vitro. Commercial curcumin isolated from the rhizome of the plant Curcuma longa Linn contains 3 major curcuminoids (approximately 77% curcumin, 17% demethoxycurcumin, and 3% bisdemethoxycurcumin). Commercial curcumin, pure curcumin, and demethoxycurcumin are about equipotent as inhibitors of TPA-induced tumor promotion in mouse skin, whereas bisdemethoxycurcumin is somewhat less active. Topical application of curcumin inhibits tumor initiation by B[a]P and tumor promotion by TPA in mouse skin. Dietary curcumin (commercial grade) inhibits B[a]P-induced forestomach carcinogenesis, N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG)-induced duodenal carcinogenesis, and azoxymethane (AOM)-induced colon carcinogenesis. Dietary curcumin had little or no effect on 4-(methylnitosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung carcinogenesis and 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast carcinogenesis in mice. Poor circulating bioavailability of curcumin may account for the lack of lung and breast carcinogenesis inhibition.
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PMID:Inhibitory effects of curcumin on tumorigenesis in mice. 959 Nov 90

Recent studies have suggested that autocrine production of Neuregulin (NRG), a growth factor that activates members of the Epidermal Growth Factor Receptor/ErbB family of proto-oncogenes, is sufficient for breast tumor initiation and progression. To elucidate the molecular mechanisms regulating these events, we undertook a global analysis of genes regulated by NRG in luminal mammary epithelial cell lines. Gene expression profiling of estrogen receptor-positive T47D cells exposed to NRG-1 revealed both previously identified and novel targets of NRG activation. Profiling of other estrogen receptor-positive breast cancer cell lines, MCF7 and SUM44, yielded a group of twenty-one genes whose transcripts are upregulated by NRG in all three lines tested. The NRG targets are FBJ murine osteosarcoma viral oncogene homolog B, Early growth response 1, v-jun avian sarcoma virus 17 oncogene homolog, Activating transcription factor 3, Homo sapiens cDNA FLJ31636 fis, Jun B proto-oncogene, Forkhead box C1, Platelet/endothelial cell adhesion molecule 1, NADPH-dependent retinol dehydrogenase/reductase, Dual specificity phosphatase 5, NGF inducible protein TIS21, Connective tissue growth factor, Jun D proto-oncogene, Serum response factor, Cullin 1, v-myc avian myelocytomatosis viral oncogene, Transient receptor potential channel 1, Low density lipoprotein receptor, Transforming growth factor beta 1, Nucleoporin 88 kDa, and Pleckstrin homology-like domain A1. Since NRG activation of these cells induces resistance to anti-hormonal therapy, the identified genes may provide clues to molecular events regulating mammary tumor progression and hormone independence.
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PMID:Neuregulin-regulated gene expression in mammary carcinoma cells. 1596 98

Previous studies have demonstrated that exposure to polycyclic aromatic hydrocarbons (PAHs) and its derivatives is associated with an increased risk of skin cancers, and the carcinogenic effect of PAHs is thought to involve both tumor initiation and promotion. Whereas PAH tumor initiation is well characterized, the mechanisms involved in the tumor promotion of PAHs remain elusive. In the present study, we investigated the effects of PAHs on vascular endothelial growth factor (VEGF) expression by comparison of its induction between the active metabolite and its parent compound (B[a]PDE versus B[a]P) or between active compound and its relatively inactive analog (5-MCDE versus CDE). We found that exposure of cells to (+/-)-anti-benzo-[a]pyrene-7,8-diol-9,10-epoxide (B[a]PDE) or (+/-)-anti-5-methylchrysene-1,2-diol-3,4-epoxide (5-MCDE) led to marked induction of VEGF in Cl41 cells, whereas benzo[a]pyrene (B[a]P) or chrysene-1,2-diol-3,4-epoxide (CDE) did not exhibit significant inductive effects. Exposure of cells to B[a]PDE and 5-MCDE did not induce HIF-1alpha activation, whereas AP-1 was significantly activated. Moreover, overexpression of TAM67 (a dominant-negative mutant c-Jun) dramatically blocked that VEGF induction. Electrophoretic mobility shift assay showed that AP-1 was only able to specifically recognize and bind to its AP-1 potential binding site within -1136 and -1115 of the VEGF promoter region. Site-directed mutation of this AP-1 binding site eliminated the VEGF transcriptional activity induced by B[a]PDE, suggesting that the AP-1 binding site between -1136 and -1115 in the VEGF promoter region is critical for VEGF induction by B[a]PDE. In addition, overexpression of Deltap85 (a dominant-negative mutant PI-3K) impaired B[a]PDE- and 5-MCDE-induced VEGF induction. Considering our previous findings that PI-3K is an upstream mediator for c-Jun/AP-1 activation, we conclude that the VEGF induction by B[a]PDE and 5-MCDE is through PI-3K/AP-1-dependent and HIF-1alpha-independent pathways. These findings may help us to understand the mechanisms involved in PAH carcinogenic effects.
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PMID:Effects of polycyclic aromatic hydrocarbons (PAHs) on vascular endothelial growth factor induction through phosphatidylinositol 3-kinase/AP-1-dependent, HIF-1alpha-independent pathway. 1646 51

Although almost two decades of study point to a central role for aberrant ErbB2 activation in breast cancer, many cellular and biochemical mechanisms underlying ErbB2-induced tumor initiation and progression remain to be resolved. A study by Guo et al. published recently in Cell indicates that the signaling function of beta4 integrin actively contributes to the initiation, growth, and invasion of ErbB2-induced mammary tumors in transgenic mice by promoting the activation of c-Jun and STAT3. These observations offer novel mechanistic insight into ErbB2 action and highlight the notion that ErbB2 co-opts the functions of other signaling proteins to elicit tumor progression.
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PMID:Co-opted integrin signaling in ErbB2-induced mammary tumor progression. 1690 7

Esophageal squamous cell carcinoma (SCC) is responsible for approximately one-sixth of all cancer-related mortality worldwide. This malignancy has a multifactorial etiology involving several environmental, dietary and genetic factors. Since esophageal cancer has often metastasized at the time of diagnosis, current treatment modalities offer poor survival and cure rates. Chemoprevention offers a viable alternative that could well be effective against the disease. Clinical investigations have shown that primary chemoprevention of this disease is feasible if potent inhibitory agents are identified. The Fischer 344 (F-344) rat model of esophageal SCC has been used extensively to investigate the biology of the disease, and to identify chemopreventive agents that could be useful in human trials. Multiple compounds that inhibit tumor initiation by esophageal carcinogens have been identified using this model. These include several isothiocyanates, diallyl sulfide and polyphenolic compounds. These compounds influence the metabolic activation of esophageal carcinogens resulting in reduced genetic (DNA) damage. Recently, a few agents have been shown to inhibit the progression of preneoplastic lesions in the rat esophagus into tumors. These agents include inhibitors of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and c-Jun [a component of activator protein-1 (AP-1)]. Using a food-based approach to cancer prevention, we have shown that freeze-dried berry preparations inhibit both the initiation and promotion/progression stages of esophageal SCC in F-344 rats. These observations have led to a clinical trial in China to evaluate the ability of freeze-dried strawberries to influence the progression of esophageal dysplasia to SCC.
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PMID:Chemoprevention of esophageal squamous cell carcinoma. 1747

Recently, enzymes of the tricarboxylic acid (TCA) cycle have emerged as novel tumor suppressors. In particular, mutations in the nuclear-encoded subunits of succinate dehydrogenase (SDHB, SDHC, and SDHD) cause paragangliomas and pheochromocytomas. Although the mechanism(s) by which disruption of mitochondrial metabolism leads to neoplasia is largely unknown, increasing evidence points to an activation of pseudohypoxia. In this study, we have shown that silencing of SDHB using DNA-based small interfering RNA resulted in major impairments in cellular proliferation, respiration, and a corresponding shift to glycolysis. The levels of reactive oxygen species, however, were unchanged. As expected, hypoxia-inducible factor-1 alpha (HIF-1 alpha) and HIF-2alpha were up-regulated in chronically silenced cells, suggesting that a pseudohypoxic state was attained. In addition, the c-Jun amino-terminal kinase and p38 kinase stress signaling proteins were hyperphosphorylated in SDHB-silenced cells. Microarray analysis showed that >400 genes were influenced (6-fold or more up-regulation or down-regulation) by silencing of SDHB, confirming the importance of the TCA cycle in cellular metabolism. Examples of dysregulated genes included those involved in proliferation, adhesion, and the hypoxia pathway. Of interest, SDHB-silenced cells had a greater capacity to adhere to extracellular matrix components, including fibronectin and laminin, than control cells, thus suggesting a possible mechanism of tumor initiation. Although transient silencing of the HIF-1 alpha transcription factor in SDHB-silenced cells had little effect on the expression of a subset of up-regulated genes, it partially reversed the adhesion phenotype to fibronectin, pointing to a potentially important role for HIF-1 in this process.
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PMID:Cells silenced for SDHB expression display characteristic features of the tumor phenotype. 1851 64

c-Jun NH(2)-terminal kinase (JNK) links several cellular processes, including proliferation and survival, and is believed to be involved in carcinogenesis. However, the role of JNK in gastric tumorigenesis is unknown. Immunohistochemical analysis reveals that JNK is frequently activated in human gastric cancer tissue. We investigated whether JNK1, a major JNK isozyme, is involved in chemically induced gastric cancer development. Mice lacking JNK1 exhibited a marked decrease in gastric carcinogenesis induced by N-methyl-N-nitrosourea, relative to their wild-type counterparts. Impaired tumor development correlated with decreased tumor initiation, which is associated with the production of reactive oxygen species. We also found that lower levels of tumorigenesis were correlated with the decreased expression of cyclin D and CDK as well as decreased cell proliferation. Taken together, JNK seems to be involved in both tumor initiation and promotion and may be an attractive target for the prevention of gastric carcinogenesis.
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PMID:c-Jun NH2-terminal kinase 1 is a critical regulator for the development of gastric cancer in mice. 1859 1

Esophageal squamous cell carcinoma (SCC) is responsible for about one-seventh of all cancer-related mortality worldwide. This disease has a multifactorial etiology involving numerous environmental, genetic, and dietary factors. The 5-year survival from esophageal SCC is poor because the disease has usually metastasized at the time of diagnosis. Clinical investigations have shown that primary chemoprevention of this disease is feasible; however, only a few agents have shown efficacy. The Fischer 344 (F-344) rat model of esophageal SCC has been used extensively to investigate the pathophysiology of the disease and to identify chemopreventive agents of potential use in human trials. Multiple compounds that inhibit tumor initiation and/or tumor progression in the rat model have been identified. These include the isothiocyanates which inhibit the metabolic activation of esophageal carcinogens and agents that inhibit the progression of dysplastic lesions to cancer including inhibitors of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), and c-Jun (a component of activator protein-1 [AP-1]). The present review deals principally with the use of berry preparations for the prevention of esophageal SCC in rodents, and summarizes recent data from a human clinical trial in China. Our results suggest that the use of berry preparations might be a practical approach to the prevention of esophageal SCC in China and, potentially, other high risk regions for this disease.
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PMID:Chemoprevention of esophageal squamous cell carcinoma with berries. 2275 84

Deregulation of c-Jun NH2-terminal kinase (JNK) signaling occurs frequently in a variety of human cancers, yet the exact role(s) of JNK deregulation in cancer cell biology remains to be fully elucidated. Our recent demonstration that the activity of JNK is required not only for self-renewal of glioma stem cells but also for their tumor initiation has, however, identified a new role for JNK in the control of the stemness and tumor-initiating capacity of cancer cells. Significantly, transient JNK inhibition was sufficient to cause sustained loss of the tumor-initiating capacity of glioma stem cells, suggesting that the phenotype of "lost tumor-initiating capacity" may be as stable as the differentiated state and that the tumor-initiating capacity might therefore be under the control of JNK through an epigenetic mechanism that also governs stemness and differentiation. Here, in this article, we review the role and mechanism of JNK in the control of this "stemness-associated tumor-initiating capacity" (STATIC), a new hypothetical concept we introduce in this review article. Since the idea of STATIC is essentially applicable to both cancer types that do and do not follow the cancer stem cell hypothesis, we also give consideration to the possible involvement of JNK-mediated control of STATIC in a wide range of human cancers in which JNK is aberrantly activated. Theoretically, successful targeting of STATIC through JNK could contribute to long-term control of cancer. Issues to be considered before clinical application of therapies targeting this JNK-STATIC axis are also discussed.
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PMID:JNK Signaling in the Control of the Tumor-Initiating Capacity Associated with Cancer Stem Cells. 2434 36


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