Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urokinase-type plasminogen activator (u-PA) contributes to tumor progression in prostate cancer (CaP). We have previously shown that u-PA expression is upregulated through the AP-1 and PEA3 sites and repressed by androgen. However, signaling pathways mediating u-PA gene expression in CaP are not delineated. We hypothesized that MAPK pathways mediate u-PA in CaP, and thereby studied specific ERK, JNK, and P38-MAPK pathway mutant constructs and inhibitors in vitro. Human, androgen insensitive CaP PC3 cells stably transfected with the androgen receptor expression vector and vector alone were used. A u-PA promoter CAT vector transiently expressed with dominant negative mutant signaling constructs was studied. All mutants drastically reduced u-PA promoter activity. Furthermore, inhibition of PI3K, an upstream regulator in the JNK/SAPK pathway, decreased u-PA promoter transcription. Collectively, these results show that MAPK pathways ERK, JNK/SAPK, and P38-MAPK represent a significant component in the regulation of u-PA expression in human CaP.
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PMID:Signal transduction-mediated regulation of urokinase gene expression in human prostate cancer. 1167 74

Overexpression of the HER2/neu oncogene (also known as c-erbB2) is a frequent molecular event in multiple human cancers, including breast and ovarian cancer. Patients with cancer that overexpress HER2/neu are associated with unfavorable prognosis, shorter relapse time, and low survival rate. Treatments that target HER2/neu expression in cancer cells have been shown to be useful strategies to significantly reverse the malignancy induced by HER2/neu overexpression. The humanized anti-HER2/neu antibody, trastuzumab (Herceptin; Genentech, Inc, South San Francisco, CA) has proven to be effective in clinical trials in patients with metastatic breast cancer. In addition, tyrosine kinase inhibitors such as emodin can also target the HER2/neu oncogenic activity. Emodin treatment inhibits HER2/neu tyrosine kinase activity and preferentially suppresses the transformation of HER2/neu-overexpressing breast cancer cells. Emodin also sensitizes HER2/neu-overexpressing cancer cells to chemotherapeutic agents, including cisplatin, doxorubicin, etoposide, and paclitaxel. Alternatively, HER2/neu overexpression can be repressed by attenuating the promoter activity of the HER2/neu gene. We have identified a number of potent transcriptional regulators, including the ets family member PEA3 and the adenovirus type 5 E1A, which are able to repress HER2/neu gene expression. Expression of these transcriptional regulators resulted in downregulation of HER2/neu promoter activity and reversed the transformed phenotype of the cancer cells in vitro. In vivo studies show that these HER2/neu repressors can act therapeutically as tumor suppressor genes for tumors that overexpress HER2/neu. These preclinical studies clearly indicate that transcriptional repressors that downregulate HER2/neu can be effective regimens for cancer treatment in a gene therapy format. More importantly, the tumor-free survival rate of treated animals is dramatically increased under nontoxic doses compared with untreated animals. A phase I clinical trial using E1A-liposome in breast and ovarian patients has recently been completed. Following treatment, we observed downregulation of the HER2/neu protein accompanied by E1A expression in both cancer and noncancer cells. Numbers of tumor cells in the pleural effusion or ascites were found to be dramatically reduced after treatment. Furthermore, apoptosis was strongly induced in the tumor cells. A phase II study has been started to further evaluate therapeutic efficacy and tumor suppression mechanisms of E1A. These studies show the clinical potential of targeting HER2/neu in cancer therapy.
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PMID:Targeting HER2: recent developments and future directions for breast cancer patients. 1177 2

E1AF is a transcription factor involved in regulation of several metastasis-associated genes, and is associated with overexpression of HER2/neu. We were unable to find a clear prognostic value of E1AF expression in human breast cancer. Furthermore, no association of E1AF levels with HER2/neu mRNA levels, hormone receptor status, histological grade, tumor size, or lymph node involvement was found.
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PMID:E1AF expression levels are not associated with prognosis in human breast cancer. 1277 89

The PEA3/E1AF/ETV4 gene encodes an Ets-related transcription factor that is expressed in the epithelial cells of the mammary gland. Previous reports have shown that PEA3 can up-regulate promoter activities of many genes associated with tumorigenesis. A significant fraction of those encode matrix metalloproteinases (MMP genes) required for degradation of the extracellular matrix. To better obtain a molecular characterization of PEA3 expression in sporadic breast cancer, we quantified PEA3 mRNA by means of real-time reverse transcriptase-polymerase chain reaction assay in a large series of human primary breast tumors. PEA3 expression showed wide variations in tumor tissues, being under-expressed in 30 of 130 (23.1%) and over-expressed in 18 of 130 (13.8%) compared with normal breast tissues. High PEA3 mRNA levels correlated significantly with Scarff-Bloom-Richardson histopathological grade III (P = 0.018) but not with poor prognosis, suggesting that PEA3 is a marker of tumor aggressiveness rather than a prognostic factor in human breast cancer. We also observed positive links between the expression of PEA3 and those of MKI67 and ERBB2 (P = 0.034 and P = 0.045, respectively) and an inverse relationship with ERalpha (P = 0.0016). Our results do not support recent findings suggesting that PEA3 could be a tumor-suppressor gene that can act therapeutically in ERBB2 over-expressed tumors. Our results also suggest major roles of the MMP2, NRG1 and CGB genes (which encode type I gelatinase, heregulin and human chorionic gonadotropin beta subunit, respectively) in the PEA3 pathway dysregulation observed in breast cancer. Taken together, the data confirm the role of the PEA3 gene in breast tumorigenesis, and suggest the existence of numerous other still unknown genes transactivated by the PEA3 transcription factor.
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PMID:Expression of PEA3/E1AF/ETV4, an Ets-related transcription factor, in breast tumors: positive links to MMP2, NRG1 and CGB expression. 1463 60

Degradation of stromal collagens in the extracellular matrix is mediated largely by matrix metalloproteinase-1 (MMP-1; collagenase-1), and high constitutive levels of MMP-1 in breast cancer correlate with a poor prognosis and invasive disease. MMP-1 expression is, in part, controlled by the mitogen-activated protein kinase (MAPK) pathway(s), which may target several activator protein-1 (AP-1) and polyoma enhancing activity-3/E26 virus (PEA3/ETS) sites within the promoter. An additional ETS site in the MMP-1 promoter is conferred by a single nucleotide polymorphism (SNP) at -1607 bp, when two guanines (5'-GGAT-3'; '2G allele/SNP') are present instead of one guanine (5'-GAT-3'; '1G allele/SNP'). This SNP is adjacent to an AP-1 site at -1602 bp, and in the presence of the 2G allele (ETS site), these sites cooperate to induce higher levels of transcription. ERK 1/2 is one component of the MAPK pathway and is constitutively active in MCF-7/ADR breast cancer cells, which are 1G/2G heterozygotes. This study demonstrates that when these cells are treated with PD098059, an ERK-specific inhibitor, MMP-1 mRNA levels are significantly decreased, suggesting that high constitutive expression of MMP-1 in these cells results from continuous ERK 1/2 activation. Using transient transfection, we determined that this signaling pathway targets different AP-1/ETS sites, depending upon which allele is present. Furthermore, in these cells, the AP-1 site at -1602 bp enhances transcription in the presence of the 2G SNP, but represses transcription from the 1G SNP. Finally, inhibiting ERK signaling and MMP-1 expression blocks type I collagen degradation and reduces the invasive ability of the MCF-7/ADR cells. We conclude that ERK 1/2 signaling and the 2G SNP mediate high levels of MMP-1 expression, which may contribute to the invasive potential of these breast cancer cells.
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PMID:The 2G single nucleotide polymorphism (SNP) in the MMP-1 promoter contributes to high levels of MMP-1 transcription in MCF-7/ADR breast cancer cells. 1469 51

Breast and ovarian cancer are two of the leading causes of death for women in the United States. HER2/neu overexpression is an unfavorable prognosis factor associated with low patient survival rate of multiple cancer types including breast and ovarian cancer. Downregulation of the HER2/neu gene expression in cancer cells has been shown to be a useful strategy to significantly reverse the malignant characteristics induced by HER2/neu overexpression. It is possible that HER2/neu overexpression can be repressed through inhibiting the promoter activity of the gene. We have identified a number of potent transcriptional regulators, including the adenovirus type 5 E1A, the SV40 large T antigen, and the ets family member PEA3, and have tested their activity to repress HER2/neu overexpression. Ectopic expression of these transcriptional regulators resulted in downregulation of the HER2/neu promoter activity and reversed the transformed phenotype of the cancer cells in vitro. These observations were followed by a series of studies to investigate whether these HER2/neu repressors could act therapeutically as tumor suppressor genes for cancers overexpressing HER2/neu. The results of these preclinical studies clearly indicated that transcriptional repressors, which downregulate HER2/neu overexpression, can be an effective regimen for cancer treatment in a gene therapy format combined with an appropriate gene delivery system such as the cationic liposome DC-Chol or replication-deficient adenovirus vector. Our results have demonstrated that these delivery systems can effectively transfer the therapeutic genes into the cancer cells in vivo and lead to significant suppressive effects on tumor growth. Furthermore, tumor-free survival rate of treated animals is increased dramatically using nontoxic doses, compared with animals without the treatment. A great body of evidence has revealed the potential of using transcriptional repressors to suppress HER2/neu overexpression and abolish tumor growth. Thus, suppression of oncogenic gene expression using transcription factors can be a novel field for cancer treatment and prevention.
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PMID:Suppressing HER2/neu-mediated cell transformation by transcriptional repressors. 1568 99

The majority of ovarian cancer patients are treated with platinum-based chemotherapy, but the emergence of resistance to such chemotherapy severely limits its overall effectiveness. We have shown that development of resistance to this treatment can modify cell signaling responses in a model system wherein cisplatin treatment has altered cell responsiveness to ligands of the erbB receptor family. A cisplatin-resistant ovarian carcinoma cell line PE01CDDP was derived from the parent PE01 line by exposure to increasing concentrations of cisplatin, eventually obtaining a 20-fold level of resistance. Whereas PE01 cells were growth stimulated by the erbB receptor-activating ligands, such as transforming growth factor-alpha (TGFalpha), NRG1alpha, and NRG1beta, the PE01CDDP line was growth inhibited by TGFalpha and NRG1beta but unaffected by NRG1alpha. TGFalpha increased apoptosis in PE01CDDP cells but decreased apoptosis in PE01 cells. Differences in extracellular signal-regulated kinase and phosphatidylinositol 3-kinase signaling were also found, which may be implicated in the altered cell response to ligands. Microarray analysis revealed 51 genes whose mRNA increased by at least 2-fold in PE01CDDP cells relative to PE01 (including FRA1, ETV4, MCM2, AXL, MT3, TRAP1, and FANCG), whereas 36 genes (including IGFBP3, TRAM1, and KRT4 and KRT19) decreased by a similar amount. Differential display reverse transcriptase-PCR identified altered mRNA expression for TCP1, SLP1, proliferating cell nuclear antigen, and ZXDA. Small interfering RNA inhibition of FRA1, TCP1, and MCM2 expression was associated with reduced growth and FRA1 inhibition with enhanced cisplatin sensitivity. Altered expression of these genes by cytotoxic exposure may provide survival advantages to cells including deregulation of signaling pathways, which may be critical in the development of drug resistance.
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PMID:Altered ErbB receptor signaling and gene expression in cisplatin-resistant ovarian cancer. 1606 61

The objective of this study was to analyze site-related expression of angiogenic molecules in breast carcinoma, with the aim of characterizing phenotypic alterations along the clinical progression from primary tumor to pleural effusion. A total of 49 malignant pleural effusions and 68 corresponding solid tumors were studied for protein and mRNA expression of vascular endothelial growth factor (VEGF) and its receptor KDR, interleukin-8 (IL-8), basic fibroblast growth factor (bFGF) and the alphaV integrin subunit using immunohistochemistry, mRNA in situ hybridization (ISH) and reverse transcription polymerase chain reaction (RT-PCR). Expression was analyzed for possible association with mRNA expression of the Ets-1 and PEA3 transcription factors. The predictive value of angiogenic molecules, PEA3 and Ets-1, and clinical parameters was analyzed for 18 patients. ISH showed the presence of VEGF, IL-8 and bFGF mRNA in the majority of specimens, irrespective of anatomic site (p > 0.05). However, protein expression of IL-8 and bFGF was lower in effusions compared to primary tumors (p = 0.001 for IL-8, p < 0.001 for bFGF). Expression of alphaV integrin showed an opposite change, with higher level in effusions compared to primary tumors (p = 0.03). bFGF and alphaV integrin expression in effusions was also altered compared to lymph node metastases (p = 0.041 and p = 0.016, respectively). IL-8 and Ets-1 (p = 0.035) and VEGF and PEA3 (p = 0.026) mRNA was co-expressed in effusions. In univariate survival analysis, bFGF protein expression in effusions (p = 0.015), PEA3 mRNA expression in primary tumors (p = 0.02) and previous radiation therapy (p = 0.034) predicted shorter disease-free survival. PEA mRNA expression in primary tumors (p = 0.002) and previous chemotherapy (p = 0.048) predicted poor overall survival, with a similar trend for advanced disease stage at diagnosis (p = 0.05). Our data provide evidence regarding molecular changes that occur along the progression of breast carcinoma from primary tumor to effusion, and suggest altered requirement of angiogenic factors in body cavities. The poor disease-free survival for patients with bFGF-positive effusions suggests a role for this growth factor in mediating tumor survival rather than angiogenesis at this site.
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PMID:Angiogenic molecule expression is downregulated in effusions from breast cancer patients. 1614 38

Overexpression of HER2 is associated with an adverse prognosis in breast cancer. Despite this, the mechanism of its transcriptional regulation remains poorly understood. PEA3, a MAP kinase (MAPK)-activated member of the Ets transcription factor family has been implicated in the transcriptional regulation of HER2. The direction of its modulation remains controversial. We assessed relative levels of PEA3 expression and DNA binding in primary breast cultures derived from patient tumours (n=18) in the presence of an activated MAPK pathway using Western blotting and shift analysis. Expression of PEA3 in breast tumours from patients of known HER2 status (n=107) was examined by immunohistochemistry. In primary breast cancer cell cultures, growth factors induced interaction between PEA3 and its DNA response element. Upregulation of PEA3 expression in the presence of growth factors associated with HER2 positivity and axillary lymph node metastasis (P=0.034 and 0.049, respectively). PEA3 expression in breast cancer tissue associated with reduced disease-free survival (P<0.001), Grade III tumours (P<0.0001) and axillary lymph node metastasis (P=0.026). Co-expression of PEA3 and HER2 significantly associated with rate of recurrence compared to patients who expressed HER2 alone (P=0.0039). These data support a positive role for PEA3 in HER2-mediated oncogenesis in breast cancer.
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PMID:A positive role for PEA3 in HER2-mediated breast tumour progression. 1706 Sep 41

The final proof about the specific mechanisms by which the different components of olive oil, the principal source of fat in a typical "Mediterranean diet", exert their potential protective effects on the promotion and progression of several human cancers requires further investigations. A recent discovery that dietary fatty acids can interact with the human genome by regulating the amount and/or activity of transcription factors has opened a whole new line of research aimed to molecularly corroborate the ant-cancer benefits of the olive oil-based Mediterranean diet and the underlying mechanisms. Our most recent findings reveal that oleic acid (OA; 18:1n-9), the main olive oil's monounsaturated fatty acid, can suppress the overexpression of HER2 (erbB-2), a well-characterized oncogene playing a key role in the etiology, invasive progression and metastasis in several human cancers. First, exogenous supplementation with physiological concentrations of OA significantly down-regulates HER2-coded p185(Her-2/neu) oncoprotein in human cancer cells naturally harboring amplification of the HER gene. Second, OA exposure specifically represses the transcriptional activity of the human HER2 gene promoter in tumor-derived cell lines naturally exhibiting HER2 gene amplification and p185(Her-2/neu) protein overexpression but not in cancer cells expressing physiological levels of HER2. Third, OA treatment induces the up-regulation of the Ets protein PEA3 (a transcriptional repressor of the HER2 gene promoter) solely in cancer cells naturally displaying HER2 gene amplification. Fourth, HER2 gene promoter bearing a PEA3 site-mutated sequence cannot be negatively regulated by OA, while treatment with OA fails to repress the expression of a human full-length HER2 cDNA controlled by a SV40 viral promoter. Fifth, OA-induced inhibition of HER2 promoter activity does not occur if HER2 gene-amplified cancer cells do no concomitantly exhibit high levels of Fatty Acid Synthase (FASN; Oncogenic antigen-519) as specific depletion of FASN, which itself similarly suppresses HER2 overexpression by inducing PEA3-dependent repression of HER2 gene promoter, strongly antagonizes the inhibitory effects of OA on HER2 gene promoter activity. Considering that OA treatment efficiently blocks FASN activity and down-regulates FASN protein expression, it is reasonable to suggest that an accumulation of supra-physiological concentrations of the FASN substrate malonyl-CoA, due to its reduced utilization by FASN in the presence of exogenous OA, appears to act as an indicator of "cell fuel" availability capable to suppress HER2 expression via formation of inhibitory "PEA3 protein-PEA3 DNA binding site" complexes on the endogenous HER2 promoter. Indeed, malonyl-CoA on its own dramatically decreases HER2 promoter activity, while OA or malonyl-CoA similarly up-regulates PEA3 gene promoter activity. This previously unrecognized ability of OA to directly affect the expression of a cluster of interrelated human cancer genes (i.e., HER2, FASN and PEA3) should open a new line of research aimed to explore the anti-cancer effects of OA. Certainly, an appropriate dietary intervention reproducing this prominent anti-oncogenic feature of the "Mediterranean diet" must be carried out in animal models and human pilot studies in the future. Only then we will know whether the old "Mediterranean dietary traditions" will become a new molecular approach in the management of cancer disease.
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PMID:Mediterranean dietary traditions for the molecular treatment of human cancer: anti-oncogenic actions of the main olive oil's monounsaturated fatty acid oleic acid (18:1n-9). 1716 66


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