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)

EGF-related peptides and their receptors play an important, but not fully understood role, both, in epithelial physiology and pathophysiology but also in human tumor carcinogenesis and tumor behavior, respectively. Overexpression of EGF-related growth factors from normal epithelium to carcinomas has been demonstrated for several human tissues such as breast, endometrium, cervix and ovary. Additionally, the differential overexpression of EGFR or erb B-2 in various malignancies has already proven to be efficacious in stratifying patients with respect to a poor prognosis. These data suggest that EGF-related growth factors, erb B receptors or signaling proteins that function either upstream or downstream from these receptors may represent novel targets for selective tumor therapy. In the future, conventional chemotherapy regimes will ultimately be wedded to more biologically-oriented therapies. One important target for these novel therapeutic approaches in solid tumors will be the EGF-related growth factors and their receptors.
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PMID:Expression and function of EGF-related peptides and their receptors in gynecological cancer--from basic science to therapy. 1071 95

The neu (c-erbB-2, Her-2) protooncogene is amplified and overexpressed in 20-30% of human breast cancers. Although transgenic mouse models have illustrated the role of Neu in the induction of mammary tumors, Neu expression in these models is driven by a strong viral promoter of questionable relevance to the human disease. To ascertain whether expression of activated Neu under the control of the endogenous promoter in the mammary gland could induce mammary tumors we have generated mice that conditionally express activated Neu under the transcriptional control of the intact endogenous Neu promoter. Expression of oncogenic neu in the mammary gland resulted in accelerated lobulo-alveolar development and formation of focal mammary tumors after a long latency period. However, expression of activated Neu under the normal transcriptional control of the endogenous promoter was not sufficient for the initiation of mammary carcinogenesis. Strikingly, all mammary tumors bear amplified copies (2-22 copies) of the activated neu allele relative to the wild-type allele and express highly elevated levels of neu transcript and protein. Thus, like human erbB-2-positive breast tumors, mammary tumorigenesis in this mouse model requires the amplification and commensurate elevated expression of the neu gene.
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PMID:Amplification of the neu/erbB-2 oncogene in a mouse model of mammary tumorigenesis. 1071 6

Medullary thyroid carcinoma (MTC) occurs sporadically (sMTC) or as part of the inherited cancer syndrome, multiple endocrine neoplasia type 2 (MEN 2). While the occurence of the MEN 2 syndrome is associated with mutations in the RET protooncogene, the reason for carcinogenesis in sMTC still remains unclear. Ras is a frequently mutated oncogene in a broad spectrum of human tumors and has been found in about 50% of follicular, papillary or anaplastic thyroid carcinomas. The purpose of this study was to determine, whether mutations in the ras oncogene could play a possible role in the carcinogenesis of sMTC. In this study we analyzed 15 sMTC for mutations in the hotspots codon 12, 13 and 61 of the H- and K-ras oncogene. We used the direct sequencing technique. In none of the examined tumors we were able to detect a mutation in the codon 12, 13 and 61 of the H-ras and K-ras oncogene. Based upon these results, we conclude that H- and K-ras do not play an important role in the carcinogenesis of sMTC.
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PMID:Absence of H- and K-ras oncogene mutations in sporadic medullary thyroid carcinoma. 1076 32

Tumor transplants into nude mice (NM) may reveal abnormal biological behavior compared with the original tumor. Despite this, human tumor xenografts in NM have been widely used to study the biology of tumors and to establish diagnostic and therapeutic modalities. Clearly, precise differences in the biology of a given tumor in human and in NM cannot be assessed. We compared the growth kinetics, differentiation pattern and karyotype of an anaplastic Syrian hamster pancreatic cancer cell line in NM and in allogenic hamsters. As with the original tumor, transplants in hamsters grew fast, were anaplastic and expressed markers related to tumor malignancy like galectin 3, TGF-alpha and its receptor EGFR at high levels. However, tumors in the NM were well-differentiated adenocarcinomas, grew slower, had increased apoptotic rate and had a high expression of differentiation markers such as blood group A antigen, DU-PAN-2, carbonic anhydrase II, TGF-beta(2) and mucin. Karyotypically, the tumors in the NM acquired additional chromosomal damage. Our results demonstrate significant differences in the morphology and biology of tumors grown in NM and the allogenic host, and call for caution in extrapolating data obtained from xenografts to primary cancer.
Carcinogenesis 2000 Jun
PMID:Biologic instability of pancreatic cancer xenografts in the nude mouse. 1083 99

The upper aerodigestive tract is predisposed to the formation of multiple primary tumors due to field cancerization. TGF-alpha/EGFR autocrine signaling appears to play an important role in squamous cell carcinoma of the head and neck (SCCHN) and upregulation of TGF-alpha and EGFR is an early event in SCCHN carcinogenesis. STAT proteins, including Stat3, are activated by TGF-alpha and EGFR and strategies that downmodulate TGF-alpha or EGFR inhibit SCCHN cell proliferation and abrogate Stat3 activation. Targeting Stat3 leads to SCCHN growth inhibition, increases apoptosis and a downmodulation of Bcl-xL expression in head and neck tumors. These studies support the role of Stat3 as an oncogene, which is activated early in SCCHN carcinogenesis, and efforts to understand EGFR-mediated Stat3 signaling could facilitate novel strategies that will interfere with this growth promoting pathway. Oncogene (2000).
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PMID:STAT signaling in head and neck cancer. 1085 Oct 47

In this study we have explored the involvement of oxidative stress in Cr(VI)-induced JNK, p38 and ERK signaling pathways and their effects on Cr(VI) cytotoxicity in human non-small cell lung carcinoma CL3 cells. Exposure to K(2)Cr(2)O(7) markedly activated JNK and p38 and moderately activated ERK in a dose- (10-80 microM) and time-dependent (1-12 h) manner. The activated p38 decreased markedly and rapidly and the activated JNK decreased gradually when Cr(VI) was removed from the medium. Post-incubation of Cr(VI)-treated cells with H(2)O(2) increased the activities of JNK and p38, but not ERK. Co-administering Cr(VI) with 3-amino-1,2, 4-triazole (3AT), a catalase inhibitor, enhanced p38 activation, but did not influence JNK and ERK activation by Cr(VI). Conversely, co-administering Cr(VI) with mannitol, a hydroxyl radical scavenger and a Cr(V) chelator, reduced p38 activation and increased JNK and ERK activation by Cr(VI). These results indicate that p38 activation by Cr(VI) is positively correlated with oxidative stress, while JNK activity can be enhanced by either a quencher (mannitol) or activator (H(2)O(2)) of redox reactions in Cr(VI)-exposed CL3 cells. However, both 3AT and mannitol reduced the cytotoxicity of Cr(VI), but H(2)O(2) did not. The JNK activated by Cr(VI) was decreased (approximately 50%) by expression of a kinase-defective form of MKK7 (MKK7A) but not that of MKK4 (MKK4KR), suggesting that activation of JNK by Cr(VI) is mediated through MKK7. SB202190, a specific inhibitor of p38, markedly decreased JNK but did not change ERK activation by Cr(VI). PD98059, a specific inhibitor of ERK kinases MKK1/2, blocked ERK and p38 but did not alter JNK activation by Cr(VI). Neither the specific kinase inhibitors nor expression of MKK7A altered Cr(VI)-induced cytotoxicity. Together, these results suggest that activation of the JNK, p38 and ERK pathways by Cr(VI) is mediated through diverse redox mechanisms, yet their activation does not correlate with Cr(VI) cytotoxicity.
Carcinogenesis 2000 Aug
PMID:Activation of JNK, p38 and ERK mitogen-activated protein kinases by chromium(VI) is mediated through oxidative stress but does not affect cytotoxicity. 1091 Sep 49

The RON receptor tyrosine kinase is a 180 kDa heterodimeric protein composed of a 40 kDa alpha chain and a 145 kDa beta chain with intrinsic tyrosine kinase activity. Activation of RON causes cell dissociation, motility and invasion of extracellular matrices, suggesting that RON might be involved in tumor metastasis. We report here the cloning of a novel splice variant of RON in human colorectal carcinoma cell line HT-29. This RON variant is first produced as a single chain precursor with a molecular mass of 160 kDa. Proteolytic cleavage results in a 40 kDa alpha chain and a short form of the beta chain with a molecular mass of 125 kDa. The altered receptor is synthesized from a transcript differing from the full-length RON mRNA by an in-frame deletion of 109 amino acids in the extracellular domain of the RON beta chain. The consequence of the deletion is constitutive activation of the protein with autophosphorylation. Expression of the RON variant in colon epithelial CoTr cells results in increased cell migration and invasion of extracellular matrices. These data suggest that generation of the activated splice variant of RON may contribute to the invasive phenotype of human colorectal carcinomas in vivo.
Carcinogenesis 2000 Aug
PMID:Identification of a novel splicing product of the RON receptor tyrosine kinase in human colorectal carcinoma cells. 1091 Sep 51

Increased expression of cyclooxygenase-2 (COX-2) expression has been observed in several human tumor types and in selected animal and cell culture models of carcinogenesis, including lung cancer. Increased expression of COX-2 and production of prostaglandins appear to provide a survival advantage to transformed cells through the inhibition of apoptosis, increased attachment to extracellular matrix, increased invasiveness, and the stimulation of angiogenesis. In the present studies, we found that transforming growth factor beta1 (TGF-beta1) and epidermal growth factor (EGF) synergistically induced the expression of COX-2 and prostaglandin E2 (PGE2) production in mink lung epithelial (Mv1Lu) cells. EGF, but not PDGF or IGF-1, was able to inhibit TGF-beta1-induced apoptosis in Mv1Lu cells and this effect was blocked by NS-398, a selective inhibitor of COX-2 activity, suggesting a possible role for COX-2 in the anti-apoptotic effect of EGF receptor ligands. The combination of TGF-beta1 and EGF also significantly induced COX-2 expression in rat intestinal epithelial (RIE-1) cells and completely prevented sodium butyrate (NaBu)-induced apoptosis. The synergistic induction of COX-2 by TGF-beta1 and EGF was not observed in R1B-L17 cells, a line derived from Mv1Lu cells that lacks the TGF-beta type-I receptor. AG1478, a selective inhibitor of EGF receptor tyrosine kinase activity, completely suppressed the induction of COX-2 expression by either EGF or TGF-beta1+EGF. Also, PD98059, a specific inhibitor of MEK/ERK pathway, and SB203580, a specific inhibitor of p38 MAPK activity, significantly inhibited the induction of COX-2 in response to combined EGF and TGF-beta1. These results suggest an important collaborative interaction of TGF-beta1 and EGF signaling in the induction of COX-2 and prostaglandin production in Mv1Lu cells.
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PMID:Synergistic induction of cyclooxygenase-2 by transforming growth factor-beta1 and epidermal growth factor inhibits apoptosis in epithelial cells. 1093 98

Investigation of early breast carcinogenesis is limited by the difficulty in obtaining cell cultures or adequate fresh frozen material and by the fact that available data from in situ techniques are interpreted in terms of various classification systems. Our studies in a series of pure ductal carcinomas in situ (DCIS) were conducted in accordance with the recommendations of the international Consensus Conference (Hum. Pathol., 28, 122-125, 1997) relative to processing, determination of lesion extent, and histological stratification primarily on nuclear grade (NG). A multifactorial study performed in 15 low- and 16 high-NG DCIS (68% detected by mammography) included the following: (1) morphological analysis of NG, necrosis, and architectural pattern; (2) detection of numerical genomic abnormalities at ERBB2, MYC, CCND1, Xq1.2 and 20q13 loci by fluorescence in situ hybridization on interphase nuclei; and (3) immunohistochemical determination of cell proliferation, p53 accumulation, hormonal receptors and bcl-2 expression on serial sections of formalin-fixed, paraffin-embedded specimens. High NG, comedo/solid pattern and necrosis were significantly associated with amplification at one or more loci, the number of amplified loci, amplification at the ERBB2 locus, absence of bcl-2 and hormonal receptor expression and high cell proliferation (p < 0.05). High NG and comedo/solid pattern were significantly associated with MYC amplification and p53 accumulation, and necrosis with CCND1 amplification (the only gene amplification detected in low NG DCIS). These data provide additional information on the early steps of breast carcinogenesis, in accordance with currently recognized criteria of histological classification.
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PMID:Gene amplifications detected by fluorescence in situ hybridization in pure intraductal breast carcinomas: relation to morphology, cell proliferation and expression of breast cancer-related genes. 1100 1

Breast cancer is characterized by an important histoclinical heterogeneity that currently hampers the selection of the most appropriate treatment for each case. This problem could be solved by the identification of new parameters that better predict the natural history of the disease and its sensitivity to treatment. A large-scale molecular characterization of breast cancer could help in this context. Using cDNA arrays, we studied the quantitative mRNA expression levels of 176 candidate genes in 34 primary breast carcinomas along three directions: comparison of tumor samples, correlations of molecular data with conventional histoclinical prognostic features and gene correlations. The study evidenced extensive heterogeneity of breast tumors at the transcriptional level. A hierarchical clustering algorithm identified two molecularly distinct subgroups of tumors characterized by a different clinical outcome after chemotherapy. This outcome could not have been predicted by the commonly used histoclinical parameters. No correlation was found with the age of patients, tumor size, histological type and grade. However, expression of genes was differential in tumors with lymph node metastasis and according to the estrogen receptor status; ERBB2 expression was strongly correlated with the lymph node status (P < 0.0001) and that of GATA3 with the presence of estrogen receptors (P < 0.001). Thus, our results identified new ways to group tumors according to outcome and new potential targets of carcinogenesis. They show that the systematic use of cDNA array testing holds great promise to improve the classification of breast cancer in terms of prognosis and chemosensitivity and to provide new potential therapeutic targets.
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PMID:Gene expression profiling of primary breast carcinomas using arrays of candidate genes. 1111 42


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