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

Persistent Rel/nuclear factor-kappaB (NF-kappaB) activity is a hallmark of many human cancers, and the Rel proteins are implicated in leukemia/lymphomagenesis but the mechanism is not fully understood. Microarray analysis to identify transformation-impacting genes regulated by NF-kappaB's oncogenic v-Rel and c-Rel proteins uncovered that Rel protein expression leads to transcriptional repression of key B-cell receptor (BCR) components and signaling molecules like B-cell linker (BLNK), the B-cell adaptor for phosphoinositide 3-kinase (BCAP) and immunoglobulin lambda light chain (Ig lambda), and is accompanied by a block in BCR-mediated activation of extracellular signal-regulated kinase, Akt, and c-Jun-NH(2)-kinase in response to anti-IgM. The BLNK and BCAP proteins were also down-regulated in lymphoid cells expressing a transformation-competent chimeric RelA/v-Rel protein, suggesting a correlation with the capacity of Rel proteins to transform lymphocytes. DNA-binding studies identified functional NF-kappaB-binding sites, and chromatin immunoprecipitation (ChIP) data showed binding of Rel to the endogenous blnk and bcap promoters in vivo. Importantly, restoration of either BLNK or BCAP expression strongly inhibited transformation of primary chicken lymphocytes by the potent NF-kappaB oncoprotein v-Rel. These findings are interesting because blnk and other BCR components and signaling molecules are down-regulated in primary mediastinal large B-cell lymphomas and Hodgkin's lymphomas, which depend on c-Rel for survival, and are consistent with the tumor suppressor function of BLNK. Overall, our results indicate that down-regulation of BLNK and BCAP is an important contributing factor to the malignant transformation of lymphocytes by Rel and suggest that gene repression may be as important as transcriptional activation for Rel's transforming activity.
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PMID:Repression of B-cell linker (BLNK) and B-cell adaptor for phosphoinositide 3-kinase (BCAP) is important for lymphocyte transformation by rel proteins. 1824 82

Osteoporosis is a reduction in skeletal mass due to an imbalance between bone resorption and bone formation. Bone morphogenetic protein (BMP) plays important roles in osteoblastic differentiation and bone formation. Therefore, components involved in BMP activation are good targets for the development of anti-osteoporosis drugs. In this study, naringin a polymethoxylated flavonoid, was shown to enhance alkaline phosphatase activity, osteocalcin level, osteopontin synthesis and cell proliferation in primary cultured osteoblasts. Naringin increased mRNA and protein levels of BMP-2 using Western blot, ELISA and RT-PCR assay. In addition, naringin also prevented the decreasing of BMP-2 and bone loss inducing by ovariectomy in vivo. The transcriptional regulation of BMP-2 by naringin was mediated by phosphorylation of Akt and activation of the activator protein-1 (AP-1) components c-Fos and c-Jun. The binding of c-Fos and c-Jun to the AP-1 element on the BMP-2 promoter was enhanced by naringin. Transfection with dominant-negative mutant of p85 and Akt or c-Fos and c-Jun antisense oligonucleotide inhibited the potentiating action of naringin on BMP-2 production. Taken together, our results provide evidence that naringin increase BMP-2 expression and enhance osteogenic response via the phosphoinositide 3-kinase (PI3K), Akt, c-Fos/c-Jun and AP-1-dependent signaling pathway.
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PMID:Naringin-induced bone morphogenetic protein-2 expression via PI3K, Akt, c-Fos/c-Jun and AP-1 pathway in osteoblasts. 1849 16

Transforming growth factor-beta (TGF-beta) cooperates with oncogenic members of the Ras superfamily to promote cellular transformation and tumor progression. Apart from the classic (H-, K-, and N-) Ras GTPases, only the R-Ras subfamily (R-Ras, R-Ras2/TC21, and R-Ras3/M-Ras) has significant oncogenic potential. In this study, we show that oncogenic R-Ras transformation of EpH4 cells requires TGF-beta signaling. When murine EpH4 cells were stably transfected with a constitutively active R-Ras(G38V) mutant, they were no longer sensitive to TGF-beta-mediated growth inhibition and showed increased proliferation and transformation in response to exogenous TGF-beta. R-Ras/EpH4 cells require TGF-beta signaling for transformation to occur and they produce significantly elevated levels of endogenous TGF-beta, which signals in an autocrine fashion. The effects of TGF-beta are independent of Smad2/3 activity and require activation of TGF-beta-associated kinase 1 (TAK1) and its downstream effectors c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase as well as the phosphoinositide 3-kinase/Akt and mammalian target of rapamycin pathways. Thus, TAK1 is a novel link between TGF-beta signaling and oncogenic R-Ras in the promotion of tumorigenesis.
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PMID:Transforming growth factor-beta (TGF-beta) and TGF-beta-associated kinase 1 are required for R-Ras-mediated transformation of mammary epithelial cells. 1867 46

The Akt and mitogen-activated protein kinase (MAPK) pathways have been implicated in tumor cell survival and contribute to radiation resistance. However, the molecular basis for link between MAPK and Akt in cell survival response to radiation is unclear. Here, we show that c-Src-Rac1-p38 MAPK pathway signals Akt activation and cell survival in response to radiation. Ionizing radiation triggered Thr(308) and Ser(473) phosphorylation of Akt. Exposure of cells to radiation also induced p38 MAPK and c-Jun NH(2)-terminal kinase activations. Inhibition of c-Jun NH(2)-terminal kinase suppressed radiation-induced cell death, whereas inhibition of p38 MAPK effectively increased sensitivity to radiation. Interestingly, inhibition of p38 MAPK completely attenuated radiation-induced Ser(473) phosphorylation of Akt but did not affect Thr(308) phosphorylation. Conversely, overexpression of p38 MAPK enhanced Ser(473) phosphorylation of Akt in response to radiation. In addition, inhibition of p38 MAPK failed to alter phosphoinositide 3-kinase and phosphoinositide-dependent protein kinase activities. Ectopic expression of RacN17, dominant-negative form of Rac1, inhibited p38 MAPK activation and Ser(473) phosphorylation of Akt. Following exposure to radiation, c-Src was selectively activated among Src family tyrosine kinases. Inhibition of c-Src attenuated Rac1 and p38 MAPK activations and Ser(473) phosphorylation of Akt. Our results support the notion that the c-Src-Rac1-p38 MAPK pathway is required for activation of Akt in response to radiation and plays a cytoprotective role against radiation in human cancer cells.
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PMID:c-Src-p38 mitogen-activated protein kinase signaling is required for Akt activation in response to ionizing radiation. 1907 32

We recently reported that LY294002 (LY29) and LY303511 (LY30) sensitized tumor cells to drug-induced apoptosis independent of the phosphoinositide 3-kinase/Akt pathway. Here, we investigated the mechanism of LY30-induced sensitization of human neuroblastoma cells to TRAIL-mediated apoptosis. We provide evidence that LY30-induced increase in intracellular H(2)O(2) up-regulates the expression of TRAIL receptors (DR4 and DR5) in SHEP-1 cells by activating mitogen-activated protein kinases, resulting in a significant amplification of TRAIL-mediated caspase-8 processing and activity, cytosolic translocation of cytochrome c, and cell death. Involvement of the death receptors was further confirmed by the ability of blocking antibodies against DR4 and/or DR5 to inhibit LY30-induced TRAIL sensitization. Pharmacologic inhibition of c-Jun NH(2) terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) activation by SP600125 and PD98059, respectively, blocked LY30-induced increase in sensitization to TRAIL-mediated death. Finally, small interfering RNA-mediated gene silencing of JNK and ERK inhibited LY30-induced increase in surface expression of DR4 and DR5, respectively. These data show that JNK and ERK are two crucial players involved in H(2)O(2)-mediated increase in TRAIL sensitization of tumor cells upon exposure to LY30 and underscore a novel mode of action of this inactive analogue of LY29. Our findings could have implications for the use of LY30 and similar compounds for enhancing the apoptotic sensitivity of neuroblastoma cells that often become refractory to chemotherapy.
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PMID:LY303511 enhances TRAIL sensitivity of SHEP-1 neuroblastoma cells via hydrogen peroxide-mediated mitogen-activated protein kinase activation and up-regulation of death receptors. 1922 50

This study first investigates the anti-metastatic effect of alpha-tomatine in the human lung adenocarcinoma cell line: A549. In this study, we first noted alpha-tomatine inhibited A549 cells invasion and migration by wound-healing assay and Boyden chamber assay. The data also showed alpha-tomatine could inhibit phosphorylation of Akt and extracellular signal-regulated kinase 1 and 2 (ERK1/2), which is involved in the up-regulating matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) or urokinase-type plasminogen activator (u-PA), whereas it did not affect phosphorylation of c-Jun N-terminal kinase (JNK) and p38. Next, alpha-tomatine significantly decreased the nuclear levels of nuclear factor kappa B (NF-kappaB), c-Fos, and c-Jun. Also, treating A549 cells with alpha-tomatine also leads to a dose-dependent inhibition on the binding abilities of NF-kappaB and activator protein-1 (AP-1). Further, the treatment of inhibitors specific for PI3K (Wortmannin) or ERK (U0126) to A549 cells could cause reduced activities of MMP-2, MMP-9, and u-PA. These results showed alpha-tomatine could inhibit the metastatic ability of A549 cells by reducing MMP-2, MMP-9, and u-PA activities through suppressing phosphoinositide 3-kinase/Akt (PI3K/Akt) or ERK1/2 signaling pathway and inhibition NF-kappaB or AP-1 binding activities. These findings proved alpha-tomatine might be an anti-metastatic agent against human lung adenocarcinoma.
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PMID:Alpha-tomatine inactivates PI3K/Akt and ERK signaling pathways in human lung adenocarcinoma A549 cells: effect on metastasis. 1945 46

Penta-acetyl geniposide [(Ac)(5)GP], an acetylated geniposide product from Gardenia fructus, has been known to have hepatoprotective properties and recent studies have revealed its anti-proliferative and apoptotic effect on C6 glioma cells. In this study, we first report the anti-metastastic effect of (Ac)(5)GP in the rat neuroblastoma line: C6 glioma cells. First (Ac)(5)GP exhibited an inhibitory effect on abilities of adhesion and motility by cell-matrix adhesion assay, wound healing assay and Boyden chamber assay. Second, the decreasing activity of matrix metalloproteinase-2 (MMP-2) was noted by gelatin zymography assay. Further analysis with semi-quantitative RT-PCR showed the mRNA levels of MMP-2 and membrane type I matrix metalloproteinase (MT1-MMP) were significantly reduced, while the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) was elevated by (Ac)(5)GP treatment. Further (Ac)(5)GP also exerted an inhibitory effect on phosphoinositide 3-kinase (PI3K) protein expression, phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and inhibition of activation of transcription factor nuclear factor kappa B (NF-kappaB), c-Fos, c-Jun. These findings proved (Ac)(5)GP is highly likely to be a inhibiting cancer migration agent to be further developed in the future.
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PMID:Inhibitory effect of penta-acetyl geniposide on C6 glioma cells metastasis by inhibiting matrix metalloproteinase-2 expression involved in both the PI3K and ERK signaling pathways. 1946 79

Screening a compound library of compound 48/80 analogues, we identified 2-[5-(2-chloroethyl)-2-acetoxy-benzyl]-4-(2-chloroethyl)-phenyl acetate (E1) as a novel inhibitor of the phosphoinositide 3-kinase/Akt pathway. In order to determine the mechanism of action of E1, we analysed the effect of E1 on components of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. E1 demonstrated dose-dependent and time-dependent repression of Akt and mTOR activity in prostate and breast cancer cell lines, PC-3 and MCF-7, respectively. Inhibition of Akt and mTOR activity by E1 also coincided with increased c-Jun NH2-terminal kinase (JNK) phosphorylation. However, the mode of action of E1 is different from that of the mTOR inhibitor rapamycin. Proliferation and cell cycle analysis revealed that E1 induced cell cycle arrest and cell death in PC-3 and MCF-7 cells. Moreover, pretreatment of cancer cells with the JNK inhibitor SP600125 abolished the repression of Akt and mTOR activity by E1, indicating that the inhibition of Akt and mTOR by E1 is mediated through JNK activation. Consistently, E1 repressed Akt and mTOR activity in wild-type and p38-null mouse embryonic fibroblasts (MEFs), but not in MEFs lacking JNK1/2, and JNK-null MEFs were less sensitive to the antiproliferative effects of E1. We further showed that E1 can function cooperatively with suboptimal concentrations of paclitaxel to induce cell death in PC-3 and MCF-7 cells. Taken together, these data suggest that E1 induces cancer cell death through the JNK-dependent repression of Akt and mTOR activity and may provide a valuable compound for further development and research.
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PMID:The novel molecule 2-[5-(2-chloroethyl)-2-acetoxy-benzyl]-4-(2-chloroethyl)-phenyl acetate inhibits phosphoinositide 3-kinase/Akt/mammalian target of rapamycin signalling through JNK activation in cancer cells. 1954 88

Fisetin (3,3',4',7-tetrahydroxyflavone), a naturally occurring flavonoid, has been reported to possess some anti-cancer and anti-inflammation capabilities. In this study, fisetin has exhibited inhibitory effects on the adhesion, migration, and invasion ability of a highly metastatic PC-3 cells under non-cytotoxic concentrations. Gelatin zymography assay showed that fisetin inhibited the matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) activities. Our result also showed that fisetin could inhibit the phosphorylation of c-Jun N-terminal kinase 1 and 2 (JNK1/2) and Akt. Moreover, fisetin significantly decreased the nuclear levels of nuclear factor kappa B (NF-kappaB), c-Fos, and c-Jun, and the binding abilities of NF-kappaB and activator protein-1 (AP-1). Also, the results showed that the protein and mRNA levels of MMP-2 and MMP-9 were significantly reduced by Western blot and semi-quantitative RT-PCR. Further, treating specific inhibitors for PI3K (Wortmannin) or JNK (SP600125) to PC-3 cells could reduce the protein expressions of MMP-2 and MMP-9. These results showed fisetin could inhibit the metastatic ability of PC-3 by reducing MMP-2 and MMP-9 expressions through suppressing phosphoinositide 3-kinase/Akt (PI3K/Akt) and JNK signaling pathways. This suggested fisetin can serve as a potential candidate for treating cancer metastasis.
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PMID:Antimetastatic potential of fisetin involves inactivation of the PI3K/Akt and JNK signaling pathways with downregulation of MMP-2/9 expressions in prostate cancer PC-3 cells. 1963 75

Cells avert the development of malignancy in response to deregulated oncogene expression by activating a regulated cell death pathway. However, the molecular mechanism underlying this oncogene-induced cellular death process remains unclear. Here, we show that retroviral expression of oncogenic H-ras induced cell death in a caspase-independent manner in normal cells. Inhibition of c-Jun NH2-terminal kinase (JNK) by pretreatment with SP600125 or a dominant-negative form of JNK blocked cell death. Rac1 and phosphoinositide 3-kinase (PI3K) were activated in cells overexpressing oncogenic H-ras. Inhibition of Rac1 with RacN17, a dominant-negative form of Rac1, attenuated oncogenic H-ras-induced JNK activation and subsequent cell death. Interestingly, inhibition of PI3K with LY294002 or by small interfering RNA-mediated knockdown of PI3K p85 or p110 subunits also clearly attenuated JNK activation and cell death. No cross talk was observed between Rac1 and PI3K, indicating that these pathways operate in parallel. Our findings show that JNK is necessary for oncogenic H-ras-induced, caspase-independent cell death, and that both PI3K and Rac1 activities are required for JNK activation and cell death. Determining the molecular mechanisms that mediate cell death responses to deregulated oncogenes provides a more refined understanding of cellular disposal processes in normal cells and increases our appreciation of these events as a mechanism for protecting against malignant progression.
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PMID:Oncogenic Ras signals through activation of both phosphoinositide 3-kinase and Rac1 to induce c-Jun NH2-terminal kinase-mediated, caspase-independent cell death. 1972 72


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