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)

Wilms tumor is a pediatric neoplasm that arises from the metanephric blastema. The expression of the gene encoding insulin-like growth factor II (IGF-II) is often elevated in these tumors. Since many of the actions of IGF-II are mediated through activation of the IGF-I receptor (IGF-IR), we have measured the levels of IGF-IR mRNA in normal kidney and in Wilms tumor samples using solution hybridization/RNase protection assays. IGF-IR mRNA levels in the tumors were 5.8-fold higher than in adjacent normal kidney tissue. Among the tumors themselves, the levels of IGF-IR mRNA in those containing heterologous stromal elements were 2-fold higher (P < 0.01) than in tumors without these elements. IGF-IR gene (designated IGF1R) expression in the tumors was inversely correlated with the expression of the Wilms tumor suppressor gene WT1, whose inactivation appears to be a key step in the etiology of Wilms tumor. Cotransfection of Chinese hamster ovary cells with rat and human IGF-IR gene promoter constructs driving luciferase reporter genes and with WT1 expression vectors showed that the active WT1 gene product represses IGF-IR promoter activity in a dose-dependent manner. These results suggest that underexpression, deletion, or mutation of WT1 may result in increased expression of the IGF-IR, whose activation by IGF-II may be an important aspect of the biology of Wilms tumor.
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PMID:Increased expression of the insulin-like growth factor I receptor gene, IGF1R, in Wilms tumor is correlated with modulation of IGF1R promoter activity by the WT1 Wilms tumor gene product. 839 Jun 84

In patients with Denys-Drash syndrome, mutations of the Wilms' tumor suppressor gene are associated with nephroblastomas and developmental abnormalities of the genital tract and renal glomerulus. Normally, the Wilms' tumor gene product (WT1) is expressed at high levels in visceral glomerular epithelial cells (VGEC) of the emerging fetal glomerulus. We demonstrate that WT1 could normally serve to suppress EGF receptor expression in VGEC, since immunoreactive EGF receptor is strikingly absent compared to epithelial cells of the emerging proximal and distal tubule, which lack WT1. When HEK293 cells were co-transfected with plasmids containing EGFR enhancer/promoter elements linked to a CAT reporter and plasmids containing WT1 cDNA, EGFR enhancer/promoter activity was suppressed by all wild-type WT1 isoforms, but not by deletion mutants of WT1 lacking normal zinc-finger or N-terminal domains. Surprisingly, plasmids expressing a Denys-Drash WT1 mutant (R394W) retained the ability to suppress EGFR promoter activity in this system. Furthermore, we found that immunoreactive EGFR was appropriately undetectable in glomeruli from a three-year-old girl with Denys-Drash syndrome and in sections of her Wilm's tumor. These data suggest that faulty suppression of EGFR cannot account for the abnormalities of glomerulogenesis seen in Denys-Drash patients.
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PMID:Regulation of renal EGF receptor expression is normal in Denys-Drash syndrome. 929 Nov 79

The Wilms' tumour suppressor gene WT1 encodes a zinc finger protein that is mutated in a subset of Wilms' tumours. Mutation screening and animal studies revealed essential roles during development and later function of the kidneys and the entire genitourinary system. Sequence similarity suggested a possible role for WT1 as a transcription factor. Indeed, sequence specific DNA binding and transcriptional activation or repression potential could be demonstrated in transient transfection assays with various reporter constructs. To identify endogenous WT1 target genes we established HEK293 cell lines expressing the different WT1 isoforms in a tetracycline dependent manner. Differential display PCR (ddPCR) was performed on RNA from stable WT1 transfected HEK293 cell lines and two other WT1 transfected lines (G401 and Saos-2). In an extended survey of several thousand ddPCR bands only few differences in intensity were seen and none of these could unambiguously be verified as being WT1 regulated by subsequent Northern blot analysis. In addition, almost none of the WT1 target genes identified to date in transient co-transfection assays could be confirmed by either ddPCR or Northern hybridization in the three stable transfected cell lines. Among the nine genes expressed, the only exceptions were CSF1 and to a lesser extent IGF1R being induced in Saos-2/G401 and HEK293 cells, respectively. At least two of the cell lines tested had previously shown clear biological effects though -- either WT1 dependent apoptosis (Saos-2) or greatly reduced tumorigenicity (G401). This suggests that WT1 may regulate only a very small set of genes that escape the detection methods used or it may not act as a transcription factor that influences steady state levels of mRNA.
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PMID:Analysis of WT1 target gene expression in stably transfected cell lines. 977 72

C-cell hyperplasias are normally multifocal in multiple endocrine neoplasia type 2A. We compared clonality, microsatellite pattern of tumor suppressor genes, and cellular kinetics of C-cell hyperplasia foci in each thyroid lobe. We selected 11 females from multiple endocrine neoplasia type 2A kindred treated with thyroidectomy due to hypercalcitoninemia. C-cell hyperplasia foci were microdissected for DNA extraction to analyze the methylation pattern of androgen receptor alleles and microsatellite regions (TP53, RB1, WT1, and NF1). Consecutive sections were selected for MIB-1, pRB1, p53, Mdm-2, and p21WAF1 immunostaining, DNA content analysis, and in situ end labeling. Appropriate tissue controls were run. Only two patients had medullary thyroid carcinoma foci. Nine informative C-cell hyperplasia patients showed germline point mutation in RET, eight of them with the same androgen receptor allele preferentially methylated in both lobes. C-cell hyperplasia foci showed heterogeneous DNA deletions revealed by loss of heterozygosity of TP53 (12 of 20), RB1 (6 of 14), and WT1 (4 of 20) and hypodiploid G0/G1 cells (14 of 20), low cellular turnover (MIB-1 index 4.5%, in situ end labeling index 0.03%), and significantly high nuclear area to DNA index ratio. MEN 2A (germline point mutation in RET codon 634) C-cell hyperplasias are monoclonal and genetically heterogeneous and show down-regulated apoptosis, findings consistent with an intraepithelial neoplasia. Concordant X-chromosome inactivation and interstitial gene deletions suggest clone expansions of precursors occurring at a point in embryonic development before divergence of each thyroid lobe and may represent a paradigm for other germline mutations.
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PMID:Germline RET 634 mutation positive MEN 2A-related C-cell hyperplasias have genetic features consistent with intraepithelial neoplasia. 1150 37

Eighty-two unselected cases of therapy-related myelodysplasia (t-MDS) or acute myeloid leukemia (t-AML) were investigated for internal tandem duplications of the FLT3 gene (FLT3/ITD), for internal tandem duplications of the MLL gene (MLL/ITD) and for mutations of the WT1 gene. FLT3/ITD were observed in three patients, another two patients presented MLL/ITD whereas mutations of the WT1 gene were not observed. All FLT3/ITD included the tyrosine-rich stretch between codons 589 and 599, and both MLL/ITD presented break points within Alu-repeats, as previously observed in de novo AML. The ITD were not related to any specific type of previous therapy, but three out of the five cases were observed among only six patients with overt t-AML and a normal karyotype (P = 0.0043). Interestingly, one of the patients with FLT3/ITD presented overt t-AML of subtype M1 with a normal karyotype after treatment with an alkylating agent. Complete remission was observed following treatment with daunorubicin and cytosine arabinoside, but after 37 months the patient relapsed with t-AML of subtype M3 with a t(15;17) and the same FLT3/ITD was still present. Thus FLT3/ITD may in this case represent a primary event in leukemogenesis, whereas the t(15;17) may represent a secondary event most likely induced by subsequent therapy. In conclusion, FLT3/ITD and MLL/ITD are mainly observed in uncharacteristic cases of t-AML with a normal karyotype and unrelated to previous therapy for which reason they could represent sporadic cases of de novoAML.
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PMID:Internal tandem duplications of the FLT3 and MLL genes are mainly observed in atypical cases of therapy-related acute myeloid leukemia with a normal karyotype and are unrelated to type of previous therapy. 1175 4

Immunohistochemistry (IHC) is a rapid morphological method that allows the detection of proteins involved in different mechanisms of cancer development. It is therefore a useful tool in the study of cancerogenesis. The best known example is the product of the p53 gene, a tumour suppressor gene which is altered in 50% of all human tumors. In fact, these p53 gene mutations lead to cell protein accumulation whereas the p53 product is not detectable in normal cells. This method also enables the detection of fusion proteins which result from chimeric transcript like WT1 in desmoplastic small round cell tumors, ALK in anaplastic large-cell lymphomas and FLI-1 in Ewing's sarcomas. On the contrary, gene inactivation can induce loss of immunostaining. hMLH1 and hMSH2, which are committed in DNA mismatch repair, can be altered in familial digestive carcinomas, such as hereditary non polyposis colorectal cancer. Thus IHC, which allows us to focus on the altered gene by loss of its product in tumoral cells, represents a good alternative to molecular analysis. IHC is also useful to detect the product of oncogene overexpression such as HER-2 in some breast carcinomas, which allows appropriate therapeutic protocols. Finally, IHC can be used in diagnostic, prognostic and therapeutic ends. Nevertheless, difficulties can be en- countered in the interpretation of the results. Therefore, IHC must be performed in quality control trials.
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PMID:[Immunohistochemistry and genotype analysis of tumors. First part: Which future for the immunochemical diagnosis of cancer?]. 1212 91

Desmoplastic small round cell tumor is a rare tumor typically involving peritoneum. Although the histogenesis of desmoplastic small round cell tumor has yet to be elucidated, immunophenotypical and morphological analysis shows a characteristic divergent phenotype overlapping with other round cell tumors such as Ewing's sarcoma/primitive neuroectodermal tumor, rhabdomyosarcoma, small cell mesothelioma, and carcinoma. Detection of the EWS-WT1 gene fusion is characteristic of desmoplastic small round cell tumor and has been used reliably in tumor diagnosis. In this study, we evaluated the immunophenotype of 23 desmoplastic small round cell tumor cases with the EWS-WT1 gene fusion product identified by reverse transcription-polymerase chain reaction. Paraffin sections were stained with antibodies against calretinin, WT1 (C19), desmin, myoglobin, MyoD, Myf5, myogenin, placental alkaline phosphatase, cytokeratins, MIC2, HER2/neu and c-kit using standard immunohistochemical methods. Immunoreactivity was evaluated semiquantitively by light microscopy. Desmoplastic small round cell tumors showed reactivity with calretinin in 4/21, desmin in 21/23, myoglobin in 5/17, placental alkaline phosphatase in 17/21, HER2/neu in 7/18 (3+ in 1 and 1+ in 6), c-kit in 2/14, MIC2 in 13/23, WT1 in 16/23, CAM5.2 in 21/23, and AE1/3 in 16/23 cases. The most sensitive myogenic and epithelial markers are desmin and CAM 5.2. Although nuclear reactivity of the early myogenic regulatory factors (MyoD, myogenin, Myf5) was not detected, myoglobin immunoreactivity was present in 29% of desmoplastic small round cell tumors. HER2/neu overexpression (3+) and c-kit expression are uncommon in desmoplastic small round cell tumors. A panel of myogenic and epithelial markers should be used to detect the divergent phenotype in desmoplastic small round cell tumors, a key feature in the differential diagnosis. Detection of EWS-WT1 fusion becomes critical for the diagnosis when the characteristic divergent phenotype cannot be detected immunohistochemically.
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PMID:Immunophenotype of desmoplastic small round cell tumors as detected in cases with EWS-WT1 gene fusion product. 1264 Jan 3

To determine the possible role of the epigenetic mechanisms in carcinogenesis of the hepatocellular carcinoma, we methylation-profiled the promoter CpG islands of twenty four genes both in HCC tumors and the neighboring non-cancerous tissues of twenty eight patients using the methylation-specific PCR (MSP) method in conjunction with the DNA sequencing. In comparison with the normal liver tissues from the healthy donors, it was found that while remained unmethylated the ABL, CAV, EPO, GATA3, LKB1, NEP, NFL, NIS and p27KIP1 genes, varying extents of the HCC specific hypermethylation were found associated with the ABO, AR, CSPG2, cyclin a1, DBCCR1, GALR2, IRF7, MGMT, MT1A, MYOD1, OCT6, p57KIP2, p73, WT1 genes, and demethylation with the MAGEA1 gene, respectively. Judged by whether the hypermethylated occurred in HCC more frequently than in their neighboring normal tissues, the hypermethylation status of the AR, DBCCR1, IRF7, OCT6, and p73 genes was considered as the event specific to the late stage, while that the rest that lacked such a distinguished contrast, as the event specific to the early stage of HCC carcinogenesis. Among all the clinical pathological parameters tested for the association with, the hypermethylation of the cyclin a1 gene was more prevalent in the non-cirrhosis group (P=0.021) while the hypermethylated p16INK4a gene was more common in the cirrhosis group (P=0.017). The concordant methylation behaviors of nineteen genes, including the four previously studied and their association with cirrhosis has been evaluated by the best subgroup selection method. The data presented in this report would enable us to shape our understanding of the mechanisms for the HCC specific loss of the epigenetic stability of the genome, as well as the strategy of developing the novel robust methylation based diagnostic and prognostic tools.
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PMID:Methylation profiling of twenty four genes and the concordant methylation behaviours of nineteen genes that may contribute to hepatocellular carcinogenesis. 1467 55

The protein encoded by the hepatitis B viral X-gene, HBx, is essential for viral infection and has been shown to regulate gene transcription and the Ras signaling pathway including Raf, MEK, and ERK. To better understand regulatory mechanism of HBx functions, we investigated whether ERK1/2-induced phosphorylation of HBx regulates its transcriptional activity on p21(WAF1/Cip1) promoter. HBx-genotype A (WT1) and its modified HBx (WT2; (38)SSPSPS(43) in WT1 was substituted by (38)PPSSPS(43) in HBx-genotype F) were phosphorylated by ERK1/2 in vitro, although their Ser --> Ala constructs, SA1 (S(43) of WT1 to A) and SA2 (S(41) of WT2 to A), were not. HBx WT1 and WT2, but not SA2, repressed transcription from the p21(WAF1/Cip1) promoter. This repression was blocked by treatment with PD98059, an inhibitor of MEK, or by overexpression of dominant negative MEK1. Furthermore, WT1 and WT2 localized predominantly in the nucleus, whereas SA1 and SA2 localized to the cytoplasm, suggesting that the subcellular localization of HBx is controlled by its phosphorylation. Overall, our findings provide insight that ERK1/2-mediated phosphorylation of HBx regulates HBx function and localization, and may contribute to dysregulation of cell cycle progression leading to hepatocarcinogenesis in HBV-infected cells.
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PMID:Subcellular localization and transcriptional repressor activity of HBx on p21(WAF1/Cip1) promoter is regulated by ERK-mediated phosphorylation. 1518 45

In the literature, sufficient attention has not been paid to the precise subcellular localization of immunohistochemical signals, the knowledge of which is essential for proper interpretation of immunostains and distinction of genuine staining from biotin-associated or other nonspecific stainings. The subcellular localization of the signals can in fact be easily deduced from the known biologic or ultrastructural characteristics of the antigens. Extracellular antigens obviously are located in the extracellular compartment. Cellular antigens fall into 3 major groups: membranous, nuclear, and cytoplasmic. Membranous antigens include cell adhesion molecules (such as E-cadherin, N-CAM), cell surface/transmembrane receptors and proteins (such as tyrosine kinase receptors, most leukocyte antigens, CD10, CEA), and molecules linking surface molecules to cytoskeleton (such as beta-catenin, dystrophin). Nuclear antigens include cell cycle-associated proteins (such as cyclins, p16, Ki-67), nuclear enzymes (such as TdT), transcription factors (such as TTF-1, CDX-2, myogenin, PAX-5), tumor suppressor gene products (such as p53, p63, WT1, Rb), steroid hormone receptors (such as ER, PR), calcium-binding proteins (such as S-100 protein, calretinin), and some viral proteins (such as CMV, herpes). Cytoplasmic antigens can take up a granular pattern due to localization in organelles, granules, or secretory vesicles (such as chromogranin, hormones, lysozyme, HMB-45), fibrillary pattern attributable to the filamentous nature of the molecules (intermediate filaments and microfilaments), or diffuse or patchy pattern due to localization in the cytosol or large vesicles (such as myoglobin, albumin, thyroglobulin). Aberrant localization of the molecules, when present, can provide important insight into disease processes and aid in their diagnosis, such as loss of membranous E-cadherin expression in lobular breast carcinoma, aberrant nuclear localization of beta-catenin in colorectal adenocarcinoma, pattern of ALK staining in anaplastic large cell lymphoma correlating with the different types of chromosomal translocations, presence of additional cytoplasmic CD10 staining in the enterocytes indicative of microvillous inclusion disease, and "reversed" staining for EMA in micropapillary mammary carcinoma.
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PMID:Subcellular localization of immunohistochemical signals: knowledge of the ultrastructural or biologic features of the antigens helps predict the signal localization and proper interpretation of immunostains. 1530 32


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