Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhibition of apoptosis is an important characteristic of oncogenic transformation. The Par-4 gene product has recently been shown to be upregulated in cells undergoing apoptotic cell death, and its ectopic expression was shown to be critical in apoptosis. We demonstrate that expression of oncogenic Ras promotes a potent reduction of Par-4 protein and mRNA levels through a MEK-dependent pathway. In addition, the expression of permanently active mutants of MEK, Raf-1 or zetaprotein kinase C but not of phosphatidylinositol 3-kinase (PI 3-kinase) is sufficient to decrease Par-4 levels. These effects are independent of p53, p16 and p19, and were detected not only in fibroblast primary cultures but also in NIH 3T3 and HeLa cells, indicating that they are not secondary to Ras actions on cell cycle regulation. Importantly, restoration of Par-4 levels to normal in Ras-transformed cells makes these cells sensitive to the pro-apoptotic actions of tumor necrosis factor-alpha under conditions in which PI 3-kinase is inhibited and also severely impairs colony formation in soft agar and tumor development in nude mice, as well as increases the sensitivity of these tumors to camptothecin. This indicates that the downregulation of Par-4 by oncogenic Ras is a critical event in tumor progression.
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PMID:The downregulation of the pro-apoptotic protein Par-4 is critical for Ras-induced survival and tumor progression. 1056 48

In the human breast cancer cell line MCF-7, the nucleotides ATP gamma S and UTP, acting extracellularly through the purinergic receptor P2Y(2), lead to elevated intracellular calcium levels and increased proliferation. ATP gamma S and UTP treatment of MCF-7 cells activated transcription of the immediate early gene c-fos, an important component in the response to proliferative stimulation. c-fos induction was enhanced by co-treatment with ATP gamma S and a variety of proliferative agents including growth factors, tumour promoters and stress. Stimulation with ATP gamma S or epidermal growth factor (EGF) led to extracellular signal-regulated kinase (ERK) activation and phosphorylation of the transcription factors CREB and Elk-1. Co-stimulation synergistically activated fos expression and notably led to increased levels of ERK, CREB and EGF receptor phosphorylation, as well as hyperphosphorylation of ternary complex factor. Nevertheless, the ERK pathway does not fully account for this synergy, since fos induction was differentially sensitive to the MEK inhibitor U0126, indicating that these two agonists signal differently to this immediate early gene. Thus, extracellular nucleotides co-operate with growth factors to activate genes linked to the proliferative response in MCF-7 cells through activation of specific purinergic receptors, which thereby represent important potential targets for arresting the neoplastic progression of breast cancer cells.
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PMID:Extracellular ATP activates multiple signalling pathways and potentiates growth factor-induced c-fos gene expression in MCF-7 breast cancer cells. 1113 6

Ultraviolet (UV) irradiation causes human skin aging and skin cancer through the activation of matrix metalloproteinases (MMPs) which are responsible for the degradation of collagen and tumor progression in human skin. The molecular mechanisms of UV-induced MMPs are yet to be defined. Our previous studies and others suggest that i) the transient activation of cell surface receptors and subsequent activation of MAP kinase cascade contributes to the transcriptional up-regulation of MMPs; and ii) UV-induced expression of pro-inflammatory cytokines such as IL-1 beta and TNF-alpha may also account for the expression of MMPs. However, signaling pathway through which cytokines induce MMP expression remains to be unraveled. In this study, we investigated the pathway that leads to the IL-1 beta-induced up-regulation of MMP-1 in human keratinocytes. IL-1 beta activated epidermal growth factor (EGF) receptor in cultured human keratinocytes in a time- and dose-dependent manner. IL-1 beta-induced EGF receptor tyrosine phosphorylation started at 5 min and peaked at 10 min and remained elevated up to 40 min post IL-1 beta treatment. EGF receptor kinase inhibitor PD153035 and AG1478 inhibited IL-1 beta-induced EGF receptor tyrosine phosphorylation. To test the effect of EGF receptor transactivation on downstream components, we examined the ERK activation by IL-1 beta. We found that IL-1 beta-induced ERK phosphorylation, PD153035 and MEK inhibitor PD98059 blocked IL-1 beta-induced ERK activity. Furthermore, both inhibitors also dramatically reduced IL-1 beta-induced expression of c-jun and c-fos mRNA which are required for up-regulation of MMPs. EGF receptor kinase inhibitor PD153035 and AG1478 and MEK inhibitor PD98059 also blocked IL-1 beta induction of MMP-1 in cultured human keratinocytes. Collectively, our data indicate that IL-1 beta-induced expression of MMP-1 is mediated by transactivation of EGF receptor and through ERK pathway in human keratinocytes.
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PMID:Transmodulation of epidermal growth factor receptor mediates IL-1 beta-induced MMP-1 expression in cultured human keratinocytes. 1117 16

Previous studies have shown that EGF can induce the tyrosine phosphorylation of caveolin-1 in murine fibroblasts following ErbB1 (EGF receptor) mutation or overexpression, but the cell signaling events linking EGF action with caveolin phosphorylation are not fully established. In this regard, we examined multiple human carcinoma cell lines that express various ErbB family members, including A431 epidermoid carcinoma cells and several squamous carcinoma cell lines. In all cases, EGF treatment induced the tyrosine phosphorylation of caveolin-1 in a time- and EGF dose-dependent manner, and immunoblotting analysis revealed that this phosphorylation occurred at tyrosine-14. The EGF-dependent phosphorylation of caveolin-1 was observed at low temperatures (4 degrees C) and was enhanced by caveolae-disrupting agents (cyclodextrin), suggesting that this EGF-dependent system is in a low temperature-stable arrangement that allows for their interaction under conditions where mobility in the membrane is altered. To further assess the events linking EGF action with caveolin phosphorylation, we evaluated the ligand specificity of these responses and their dependence on known effectors of EGF receptor function. We observed that EGF and HB-EGF, but not heregulin, promoted caveolin-1 phosphorylation in A431 cells, suggesting that these responses are linked to EGF receptor activation and not solely occurring via the activation of other endogenous ErbB family members. In addition, the EGF-induced phosphorylation of caveolin-1 in A431 cells was blocked by the Src kinase antagonists PP1 and PP2, but not by the MEK inhibitor PD98059, the phosphoinositide 3-kinase inhibitors LY294002 and wortmannin, or cytoskeleton-disrupting agents, such as cytochalasin D, colchicine, and nocadazole. Altogether, these data indicate that multiple human carcinoma cells exhibit an EGF receptor-dependent tyrosine phosphorylation of caveolin-1 and that this process is sensitive to Src family kinase inhibitors. These observations support a role for caveolin tyrosine phosphorylation in the profile of cellular responses by which Src potentiates cancer progression following EGF receptor overexpression.
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PMID:Caveolin-1 phosphorylation in human squamous and epidermoid carcinoma cells: dependence on ErbB1 expression and Src activation. 1237 46

Expression of 12 matrix metalloproteinases (MMPs) after exposure of human melanoma cell lines C32TG and Mewo to nitric oxide (NO) was investigated by the reverse transcription-polymerase chain reaction. Expression of the mRNA of MMP-1, -3, -10 and -13 in C32TG cells was transcriptionally enhanced in a dose-dependent manner by exposure to an NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP) and mRNA expression of MMP-1 and -10 was similarly enhanced in Mewo cells. Exposure of C32TG cells to NO increased the MMP-1 protein concentration in the culture medium. Testing with the luciferase gene fused to the 1.5 Kbp 5'-flanking region of the human MMP-1 gene showed that exposure to NO upregulated MMP-1 promoter activity in C32TG cells. Endogenous NO production after introduction of inducible NO synthase cDNA also enhanced MMP-1 promoter activity in C32TG cells. Deletion and mutational analysis identified a critical AP-1 binding site required for NO regulation of MMP-1. A neighboring Ets motif from the AP-1 site in the promoter region acted as an accessory to enhance MMP-1 expression. Electromobility shift analysis using the AP-1 binding site showed that NO enhanced the AP-1 binding ability of nuclear factors in C32TG cells. PD98059, a selective MEK inhibitor and SB202190, a p38 MAPK inhibitor, attenuated the MMP-1 mRNA expression enhanced by NO. Thus, MMP-1 was transcriptionally enhanced by NO via MAPK (ERK and p38) pathways. The results of our study suggest that the increased expression of MMPs in response to NO may be associated with tumor progression under inflammation.
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PMID:Induction of matrix metalloproteinase gene transcription by nitric oxide and mechanisms of MMP-1 gene induction in human melanoma cell lines. 1245 29

Family members of the connective tissue growth factor, cysteine-rich 61, nephroblastoma over-expressed gene (CCN) encode cysteine-rich secreted proteins with roles in human fibrotic disorders and tumor progression. In this study, we identified a CCN family member, WISP1v, as over-expressed in human cholangiocarcinomas. Genetic analysis of WISP1v was performed on surgically resected specimens of cholangiocarcinoma. The WISP1v biological effects were analyzed using the HuCCT1 human cholangiocarcinoma cell line. The WISP1v gene was expressed in 19 of 39 cholangiocarcinoma tissues (49%) but not in normal livers. Expression of WISP1v was significantly associated with lymphatic and perineural invasion of tumor cells (P <.05), as well as a poor clinical prognosis (P <.01). In the intraductal papillary cholangiocarcinomas, WISP1v was detected only in the cases with duct wall invasion but not in the cases without duct wall invasion (P <.05). No mutation of WISP1v gene was detected in the examined samples. In vitro analysis revealed that WISP1v stimulated the invasive phenotype of cholangiocarcinoma cells with activation of both p38 and p42/p44 mitogen-activated protein kinases (MAPKs). Furthermore, WISP1v-induced cholangiocarcinoma invasion was significantly suppressed by the p38 MAPK inhibitor SB203580 but not by the p42/p44 MAPK kinase (MEK) inhibitor PD98059. Our findings suggest that WISP1v-mediated signaling is involved in the generation of invasive cellular properties and leads to progression of cholangiocarcinoma.
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PMID:Human WISP1v, a member of the CCN family, is associated with invasive cholangiocarcinoma. 1271 93

Accumulating evidence suggests that p21(Cip1) located in the cytoplasm might play a role in promoting transformation and tumor progression. Here we show that oncogenic H-RasV12 contributes to the loss of actin stress fibers by inducing cytoplasmic localization of p21(Cip1), which uncouples Rho-GTP from stress fiber formation by inhibiting Rho kinase (ROCK). Concomitant with the loss of stress fibers in Ras-transformed cells, there is a decrease in the phosphorylation level of cofilin, which is indicative of a compromised ROCK/LIMK/cofilin pathway. Inhibition of MEK in Ras-transformed NIH3T3 results in restoration of actin stress fibers accompanied by a loss of cytoplasmic p21(Cip1), and increased phosphorylation of cofilin. Ectopic expression of cytoplasmic but not nuclear p21(Cip1) in Ras-transformed cells was effective in preventing stress fibers from being restored upon MEK inhibition and inhibited phosphorylation of cofilin. p21(Cip1) was also found to form a complex with ROCK in Ras-transformed cells in vivo. Furthermore, inhibition of the PI 3-kinase pathway resulted in loss of p21(Cip1) expression accompanied by restoration of phosphocofilin, which was not accompanied by stress fiber formation. These results suggest that restoration of cofilin phosphorylation in Ras-transformed cells is necessary but not sufficient for stress fiber formation. Our findings define a novel mechanism for coupling cytoplasmic p21(Cip1) to the control of actin polymerization by compromising the Rho/ROCK/LIMK/cofilin pathway by oncogenic Ras. These studies suggest that localization of p21(Cip1) to the cytoplasm in transformed cells contributes to pathways that favor not only cell proliferation, but also cell motility thereby contributing to invasion and metastasis.
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PMID:Cytoplasmic p21Cip1 is involved in Ras-induced inhibition of the ROCK/LIMK/cofilin pathway. 1455 14

Interleukin (IL)-8 serves as a major chemoattractant for neutrophils and has also been proposed to affect cancer progression. In the present study, we show that IGF-I stimulates IL-8 mRNA expression and IL-8 secretion in the leukemic cell line HL-60. Stimulation of IL-8 expression was completely attenuated by two inhibitors of mitogen-activated protein kinase (MAPK) kinase (MEK), which phosphorylates the MAPKs extracellular-regulated kinase (ERK)1 and ERK2, and by the c-Jun NH2-terminal kinase (JNK) inhibitor SP600125. In contrast, inhibitors of p38 MAPK and phosphatidylinositol-3 kinase (PI3K) did not abrogate the effect of IGF-I. We also show that IGF-I stimulates the activation of ERK1 and ERK2, but we could not detect any effect of IGF-I on the phosphorylation of p38, JNK(p46) or JNK(p54). Collectively, our results suggest that basal JNK activity and activation of the MEK-ERK pathway are required for upregulation of IL-8 by IGF-I in HL-60 cells.
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PMID:IGF-I stimulates IL-8 production in the promyelocytic cell line HL-60 through activation of extracellular signal-regulated protein kinase. 1457 64

Activation of the Raf/MEK/ERK (MAPK) signal transduction cascade by RAS mutations has been found in a variety of human cancers. Mutations of BRAF provide an alternative route for activation of this signalling pathway. To determine the role of mutations in BRAF and KRAS2 in the neoplastic progression of Barrett's adenocarcinoma, we analysed both genes for common mutations. After microdissection, DNA of 19 Barrett's adenocarcinomas, 56 Barrett's intraepithelial neoplasias (n=29 low-grade intraepithelial neoplasia (LGIN) and n=27 high-grade intraepithelial neoplasia (HGIN)), 30 Barrett's mucosa without neoplasia and normal squamous, as well as gastric epithelium, were analysed for BRAF and KRAS2 mutation. Activating BRAF mutations were identified in 2/19 Barrett's adenocarcinomas (11%) and in 1/27 HGIN (4%). KRAS2 mutations were found in four out of 19 (21%) Barrett's adenocarcinomas examined and in three cases of HGIN (11%). In LGIN as well as in normal gastric or oesophageal mucosa, neither BRAF nor KRAS2 mutations were detected. All lesions with KRAS2 mutations had an intact BRAF gene. The status of mismatch-repair proteins was neither related to BRAF nor KRAS2 mutations. These data indicate that RAS or BRAF mutations are detected in about 32% of all Barrett's adenocarcinomas. We conclude that the disruption of the Raf/MEK/ERK (MAPK) kinase pathway is a frequent but also early event in the development of Barrett's adenocarcinoma.
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PMID:Mutations of BRAF and KRAS2 in the development of Barrett's adenocarcinoma. 1472 83

Increasingly, evidence supports the function of the helix-loop-helix protein Id-1 (inhibitor of differentiation/DNA binding-1) as an oncogene. Over-expression of Id-1 is not only observed in many types of human cancer but its expression levels have been correlated with cancer progression. However, little is known about the molecular mechanisms responsible for the function of Id-1. Recently, we and others reported that Id-1-induced cell proliferation was mediated through a Raf/MEK signalling pathway. In this study, we investigated if ectopic Id-1 expression in nasopharyngeal carcinoma cells had any protective effect on taxol-induced death, which is also regulated through Raf/MEK pathway. Using four stable Id-1 transfectant clones, we found that exogenous Id-1 expression led to phosphorylation of Raf-1 and MEK1/2 kinases, which was associated with resistance to taxol. Treatment of the Id-1 expressing cells with a MEK inhibitor, PD098059, resulted in an increased taxol-induced apoptosis rate in Id-1 transfectants compared with the vector control. In addition, the fact that the taxol-induced apoptosis rate, down-regulation of Bcl-2 and up-regulation of Bax were suppressed by PD098059 treatment in Id-1 expressing cells indicates that the Id-1 induced cellular protection against apoptosis is mediated through Raf/MEK signalling pathways. Our results suggest that Id-1 may be an upstream regulator of the Raf/MEK signalling pathway, which plays an essential role in protection against taxol-induced apoptosis. Our evidence also indicates a novel treatment strategy to increase anticancer drug-induced apoptosis through inactivation of the Id-1 protein.
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PMID:Id-1-induced Raf/MEK pathway activation is essential for its protective role against taxol-induced apoptosis in nasopharyngeal carcinoma cells. 1474 19


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