Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Oncogene dosage and expression were studied in 16 testicular neoplasms, 14 of germ cell and two of non-germ cell origin. In comparison with normal DNA, tumour DNA of a total of eight patients (seven with germ cell neoplasm and one with testicular lymphoma) showed increased dosages of KRAS2, PDGFA, EGFR, MET and PDGFB. The most frequent (occurring in six tumours) and prominent (up to 3-4-fold) increases were detected in the dosages of KRAS2 (on chromosome 12p) and PDGFA (chromosome 7p), relative to a reference locus from chromosome 2. Importantly, there was a similar increase in 12p dosage in general in these tumours, suggesting the presence of the characteristic isochromosome 12p marker. On the contrary, possible 7p polysomy (assessed by molecular methods) did not explain the PDGFA (or EGFR) changes in all cases. NRAS, MYCN, CSFIR, MYB, MYC, ABL, HRASI, TP53, and ERBB2 did not reveal any consistent alterations in tumour DNA. In RNA dot blot assays the expression of KRAS2, PDGFA, EGFR, or MYC was generally not increased in the tumour samples when compared to that in normal testicular tissue of the same patients although there was interindividual variation in mRNA levels. It thus appears that while oncogene dosage changes occur in a proportion of testis cancers, they are often part of changes in large chromosomal regions or whole arms and are seldom accompanied by altered expression.
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PMID:Oncogenes in human testicular cancer: DNA and RNA studies. 182 52

The rap1/Krev-1 gene encodes a ras-related protein that suppresses transformation by ras oncogenes. We have purified an 88 kd GTPase activating protein (GAP), specific for the rap1/Krev-1 gene product, from bovine brain. Based on partial amino acid sequences obtained from this protein, a 3.3 kb cDNA was isolated from a human brain library. Expression of the cDNA in insect Sf9 cells resulted in high level production of an 85-95 kd rap1GAP that specifically stimulated the GTPase activity of p21rap1. The complete deduced amino acid sequence is not homologous to any known protein sequences, including GAPs specific for p21ras. Northern and Western blotting analysis indicate that rap1GAP is not ubiquitously expressed and appears most abundant in fetal tissues and certain tumor cell lines, particularly the Wilms' kidney tumor, SK-NEP-1, and the melanoma, SK-MEL-3, cell lines.
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PMID:Molecular cloning of a GTPase activating protein specific for the Krev-1 protein p21rap1. 190 17

Oncogenic potential of herpes simplex virus type 2 (HSV-2) and human papillomavirus (HPV) which are both associated with occurrence of cervical cancer and the mechanism of oncogenesis by these viruses were investigated by transformation experiments in vitro. The results were obtained as follows. 1) HSV-2 induced neoplastic transformation of normal diploid cells is a multistep process. Cervical cancer associated antigen AG-4 is encoded within the specific region of HSV-2 DNA which converts immortalized cells to tumorigenic lines. 2) Tumor cells express cellular oncogene at a final stage of neoplastic transformation induced by HSV-2 and "hit and run" theory is applicable to oncogenesis of this virus. 3) Complete carcinogenesis can be mediated by HPV-16 or HPV-18 DNA under collaboration with other cofactors such as HSV-2. 4) It is suggested that neoplastic transformation induced by HPV-18 DNA is based on "hit and run" oncogenesis. 5) HPV-16 or HPV-18 DNA can immortalize primary diploid cells and convert them to fully tumorigenic phenotype by repeating cell passage. 6) It has been experimentally proved that the difference in transforming potential exists between HPV 6/11 and HPV 16/18. 7) Amplification and overexpression of c-myc oncogene was detected in transformed cells obtained by HPV-16 transfection. While overexpression of c-myc was detected in transformed cells induced by HPV-18 DNA, but no amplification was observed. On the other hand, detection of HPV, DNA and amplification or overexpression of protooncogenes was performed in cervical intraepithelial neoplasias (CIN) and invasive cervical carcinomas. The results were summarized as follows. 1) HPV DNA was detected in approximately 70% of a population with CIN by in situ hybridization. CIN II showed the highest incidence of positive HPV DNA (91%), and the positive ratio decreased in CIN III (56%). 2) Immunohistochemical study of paraffin-embedded specimens with monoclonal antibodies to oncogene products revealed that only some of cervical invasive carcinomas expressed c-myc protein, ras p21 or EGFR. 3) HPV DNA was detected in 46% of invasive cervical carcinomas by Southern blot hybridization. The percentage of patients with positive results for HPV 16/18 was 29%. However, it increased up to 58% by use of polymerase chain reaction (PCR), suggesting that there are many cervical cancer tissues in which a number of cells lack viral DNA. 4) Northern blot hybridization analysis revealed overexpression of c-myc mRNA in 30% of cervical invasive carcinomas although amplification of c-myc oncogene was detected in only one of invasive carcinomas.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The possibility of viral etiology in cervical carcinogenesis]. 217 17

Functional characterization of oncogene products that induce cellular transformation has progressed rapidly in recent years. However, less is known about the mechanism(s) by which the transformed cells may escape destruction by host immune defenses and form tumors. A recently described oncogene that has an important association with aggressive human breast carcinoma is "HER2," for human epidermal growth factor receptor 2. The oncogene has also been called NGL and human c-erbB-2 (ERBB2). In this paper we show that amplification of HER2 oncogene expression can induce resistance of NIH 3T3 cells to the cytotoxic effects of recombinant tumor necrosis factor alpha (rTNF-alpha) or macrophages. Resistance is accompanied by an increased dissociation constant for rTNF-alpha binding to high-affinity receptors on the HER2-transformed NIH 3T3 cells. The resistance phenotype is independent of transformation since NIH 3T3 cells transformed by the activated human homologue of the Harvey-ras oncogene (HRAS) retain high-affinity binding sites for rTNF-alpha as well as sensitivity to its cytotoxic effects. These results suggest that HER2 may potentiate tumorigenesis by inducing tumor cell resistance to host defense mechanisms.
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PMID:Amplified expression of the HER2/ERBB2 oncogene induces resistance to tumor necrosis factor alpha in NIH 3T3 cells. 289 23

The factors that initiate and maintain the abnormal hematopoietic clone in the myelo-dysplastic syndromes (MDS) remain largely unknown. We describe a patient with MDS associated with an abnormal karyotype, 46,XY,t(5;12)(q31;p12). According to the FAB cooperative group classification, the patient was classified as chronic myelomonocytic leukemia. Because of the particular chromosomal translocation, the structure-function relationship of three genes relevant to the translocation breakpoints, CSF2, FMS, and KRAS2, was studied in bone marrow and peripheral blood lymphocytes in this patient. No major structural alterations were observed at these three genetic loci. Although the levels of expression of the CSF2 and FMS genes remained unaltered, the KRAS2 oncogene was overexpressed approximately six-fold in bone marrow cells from the MDS patient compared with normal donors. We postulate that the RAS oncogene activation may be instrumental in the genesis of MDS.
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PMID:KRAS2 oncogene overexpression in myelodysplastic syndrome with translocation 5;12. 318 12

We have previously shown that some transformed derivatives of the human osteosarcoma-derived cell line HOS are killed by treatment with 1 microM ouabain at pH 8.2, whereas their nontransformed counterparts are relatively unharmed by the same conditions. HOS cells transformed by v-Ki-ras and RAS, v-fms, or MET are susceptible to 1 microM ouabain while those transformed by v-fes are not. Here we describe the adaptation of this differentially cytotoxic effect as a method to enrich for cells which revert to a nontransformed phenotype. We have optimized parameters which increase the differential cytotoxicity, including pH and potassium concentration during and subsequent to ouabain treatment. The efficiency of this procedure was tested in mixed cell experiments where model populations were constructed consisting of HOS cells mixed with an excess of v-Ki-ras-transformed HOS cells. Two successive OAK treatments (ouabain/alkaline/K+-free) were sufficient to recover nontransformed cells free of ras-transformants as indicated by genetic markers and morphology. This HOS/ouabain system is currently being used to derive revertants of ras-transformed human cells and could facilitate the isolation of genes interacting in the pathways by which these cells are transformed.
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PMID:A system for deriving revertants of oncogene-transformed human cells. 319 49

Sodium butyrate (SB), a naturally occurring short-chain fatty acid, was investigated for its therapeutic value as an antiproliferative agent for vascular smooth muscle cells (SMCs). At 5-mmol/L concentration, SB had no significant effect on rat SMC proliferation. However, at the same concentration, SB inhibited platelet-derived growth factor (PDGF)-AA-, -AB-, and -BB-induced proliferation of SMCs. Exposure of SMCs to PDGF-BB resulted in activation of receptor intrinsic tyrosine kinase activity and autophosphorylation of beta-PDGF-receptor (beta-PDGFR). The activated beta-PDGFR physically associated and phosphorylated signaling molecules such as ras-GTPase activating protein (GAP) and phospholipase C gamma (PLC gamma). SB, in the absence of PDGF-BB, caused neither beta-PDGFR tyrosine phosphorylation nor phosphorylation and association of GAP and PLC gamma with beta-PDGFR. PDGF-BB-enhanced activation of receptor intrinsic tyrosine kinase activity and autophosphorylation of tyrosine residues of beta-PDGFR were unaffected by SB irrespective of whether SMCs were preincubated with SB before exposure to PDGF-BB plus SB or incubated concomitantly with PDGF-BB plus SB. Likewise, phosphorylation and association of GAP and PLC gamma with PDGF-BB-activated beta-PDGFR were unaffected. In addition, SB did not block PDGF-BB-stimulated, PLC gamma-mediated production of inositol triphosphate. Similarly, PDGF-BB-induced beta-PDGFR degradation was unaffected when SMCs were exposed to PDGF-BB plus SB, and SB by itself had no influence on beta-PDGFR degradation. Unlike beta-PDGFR kinase activity, mitogen-activated protein kinase (MAP-kinase) activity was stimulated by SB by about 2.7-fold. Exposure of SMCs to PDGF-BB caused an approximately 11.4-fold increase in MAP-kinase activity and this increase in activity was not significantly affected when cells were coincubated with PDGF-BB and SB (10.3-fold). However, pretreatment of SMCs with SB for 30 minutes and subsequent incubation in PDGF-BB plus SB abolished most of the PDGF-BB-induced MAP-kinase activity (4.6-fold). Transcription of growth response genes such as c-fos, c-jun, and c-myc were induced by PDGF-BB, and their induction was suppressed, particularly c-myc, by incubating SMCs with PDGF-BB plus SB. Similarly, preincubation of cells with SB for 30 minutes and subsequent incubation in PDGF-BB plus SB diminished PDGF-BB-induced transcription of c-fos, c-jun, and c-myc. However, SB by itself had no significant effect on c-fos, c-jun, and c-myc transcription.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Sodium butyrate inhibits platelet-derived growth factor-induced proliferation of vascular smooth muscle cells. 748 53

The development of effective screening tests for colorectal tumors is essential given the high frequency of these cancers in the general population, and more especially in various groups at risk. Sporadic and hereditary colorectal cancers result from the accumulation of mutations in oncogenes, such as ras, myc, neu/HER2, and in tumor suppressor genes such as apc, dcc, p53. The detection of ras or p53 mutations in DNA extracted from stool has been shown to be feasible and might be useful for the development of new screening tests. Many mutations in these genes can also be used as new prognostic factors. Identification of mutation in the apc gene responsible for familial polyposis, or its indirect detection through the study of polymorphism in such families, is completely changing the previously recommended medical attitude for the screening of this disease, and therefore may decrease or even avoid major medical follow-up. These changes are also true for the nonpolyposis hereditary colorectal tumors, also called Lynch syndrome, since the responsible hMSH2, hMLH1, hPMS1 and hPMS2 genes have recently been cloned. Mutations in these genes do not seem to be limited to families with Lynch syndrome, and could account for a predisposition of some patients to develop colorectal or other tumors.
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PMID:Contribution of molecular oncology in the detection of colorectal carcinomas. 749 39

A transcription factor ternary complex composed of Serum Response Factor (SRF) and Ternary Complex Factor (TCF) mediates the response of the c-fos Serum Response Element (SRE) to growth factors and mitogens. Three Ets domain proteins, Elk-1, SAP-1 and ERP/NET, have been reported to have the properties of TCF. Here we compare Elk-1 and SAP-1a with the human ERP/NET homologue SAP-2. All three TCF RNAs are ubiquitously expressed at similar relative levels. All three proteins contain conserved regions that interact with SRF and the c-fos SRE with comparable efficiency, but in vitro complex formation by SAP-2 is strongly inhibited by its C-terminal sequences. Similarly, only Elk-1 and SAP-1a efficiently bind the c-fos SRE in vivo; ternary complex formation by SAP-2 is weak and is substantially unaffected by serum stimulation or v-ras co-expression. All three TCFs contain C-terminal transcriptional activation domains that are phosphorylated following growth factor stimulation. Activation requires conserved S/T-P motifs found in all the TCF family members. Each TCF activation domain can be phosphorylated in vitro by partially purified ERK2, and ERK activation in vivo is sufficient to potentiate transcriptional activation.
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PMID:Comparative analysis of the ternary complex factors Elk-1, SAP-1a and SAP-2 (ERP/NET). 754 Jan 36

We have attempted to dissect signaling pathways involved in transmitting activating signals from the cell surface to the nucleus by reconstituting them in the baculovirus/Sf9 cell system. We have used this system to coexpress different combinations of the critical signaling proteins pp60v-src, p21v-ras, Raf-1 and ERK-1 and assayed the effects of resulting signaling cascades on the modifications of coexpressed transcription factors c-jun or c-fos. We observe that activation of ERK-1 via Raf-1 and p21ras dependent signals can result in the hyperphosphorylation of c-jun. In contrast, c-fos appears to be the target of two Raf-1 activated modifying signals: one independent of ERK-1 and the other dependent on ERK-1 stimulation. Thus, coexpression of c-fos with pp60v-src, p21v-ras or constitutively active forms of Raf-1 results in a dramatic reduction of its electrophoretic mobility in the absence of coexpressed ERK-1. Activation of this ERK-1-independent pathway together with the ERK-1 dependent pathway that modifies c-jun results in additional modification of c-fos. Our observation of a Raf-1 activated, ERK-independent signaling pathway is consistent with previous reports that constitutively active Raf-1 can, in some cell types, result in transformation or differentiation without activation of ERKs. Our data indicate the presence of multiple Raf-1 activated pathways that lead to modification of transcription factors.
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PMID:Reconstitution of signal transduction from the membrane to the nucleus in a baculovirus expression system: activation of Raf-1 leads to hypermodification of c-jun and c-fos via multiple pathways. 754 94


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