Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peptides of melanosomal proteins have recently been shown to be recognized in an HLA-restricted mode by specific cytolytic T lymphocytes in melanoma patients. Dendritic antigen-presenting cells (DC) are considered to be the most effective stimulators of T cell responses, and the use of these cells has therefore been proposed to generate therapeutic responses to tumor antigens in cancer patients. We, therefore, generated DC from peripheral blood of normal donors in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4. Flow cytometric analysis of the cells during a 2-week culture revealed a loss of CD14 and CD34 expression, a concomittent increase of CD1a, CD11a,b and c, CD44, CD45, CD54, HLA-class I and II, and intermediate levels of CD26, CD80 and CD86. Cultured DC stimulated proliferation of allogeneic T cells and induced a marked, up to 20-fold, stimulation of T cell proliferation after pulsing with tetanus toxoid. To achieve independence of already-identified antigenic peptides presented in HLA class I-restricted fashion, which limits the general applicability of such peptides for vaccination of melanoma patients, we tested whether DC are transfectable with eukaryotic expression plasmids. DC transfected with two reporter genes (CAT, beta-galactosidase) using a liposome-based transfection technique, exhibited only low levels of enzymatically active proteins, but were able to degrade rapidly intracellular proteins and to process peptides efficiently. Chloramphenicol acetyltransferase as well as tyrosinase mRNA were detectable after transfection by reverse-transcriptase-polymerase chain reaction, and enzyme activities became measurable. Furthermore, DC transfected with the tyrosinase gene were able to induce specific T cell activation in vitro, indicating appropriate peptide processing and presentation in DC after transfection. These data suggest new approaches to future tumor vaccination strategies.
 ...
PMID:Dendritic cells generated from peripheral blood transfected with human tyrosinase induce specific T cell activation. 748 49

Using immunostaining, immunoblot, reverse-transcriptase polymerase chain reaction and Southern blot, we found that expressions of CD44 isoforms and E-cadherin were very closely linked and were correlated with the differentiation status in human urothelial cell lines and clinical specimens of transitional cell carcinoma. Normal urothelium, well to moderately differentiated cell lines and surgical samples expressed E-cadherin and large CD44 isoforms containing exon v6, which was pivotal in metastasis of rat pancreatic cell line model. Poorly differentiated cell lines and surgical samples, were E-cadherin-negative and expressed primarily standard form CD44, which did not contain exon v6. We concluded that CD44v6 isoforms and E-cadherin were both down-regulated during the carcinogenesis of urothelium. The large exon v6 containing CD44 isoforms were readily detected in normal urothelium, therefore, were not likely linked to cancer metastasis. E-cadherin and CD44v6 may be used as differentiation markers for human urothelial tumors. Immunohistochemical study solely with antibody against epitopes encoded by exon v6 alone is not informative enough as other alternatively spliced exons may change the function of CD44v6 isoforms.
 ...
PMID:Correlation of expression of CD44 isoforms and E-cadherin with differentiation in human urothelial cell lines and transitional cell carcinoma. 753 58

In nasal biopsies from 17 adult patients with seasonal allergic rhinitis and from 10 healthy controls, cytokines were analyzed by reverse-transcriptase polymerase chain reaction (RT-PCR). The time-course study during winter included repeated local allergen provocation with subsequent nasal biopsies as well as biopsies taken during pollen season. The RT-PCR for CD44 yielded positive bands in 65 of 71 cases, in which cases mRNA for interleukins 2, 4, and 5 (IL-2, IL-4, and IL-5) were thus investigated by means of seminested PCR. IL-4 mRNA was found almost exclusively in the allergic patients. During provocation a significant increase in IL-4 was noticed compared with controls (p = 0.043). Equally, during the natural pollen season, IL-4 mRNA expression was significantly higher in patients not using nasal corticosteroids compared with those who did (p = 0.011). No differences in IL-2 or IL-5 were observed between the groups. These findings also indicate, together with earlier observations of T-cell activation, a phenotype switch toward T-helper 2 (Th2) cells, and the accumulation (homing) of these T cells in the nasal mucosa, that T cells constitute the main source for IL-4 in the nasal mucosa. Therefore, allergic patients have an increased synthesis of IL-4 when provoked with the allergen, and during natural pollen season this synthesis can be downregulated by corticosteroids. Furthermore, this study exemplifies the versatility of molecular biology in surgical pathology and that even low-copy-number cytokine mRNA can be examined in routinely snap-frozen surgical specimens.
 ...
PMID:Nasal messenger RNA expression of interleukins 2, 4, and 5 in patients with allergic rhinitis. 755 Dec 98

Peripheral lymphoid tissues contain a fibroblastic cell type referred to as stromal cells or reticulum cells which interact with lymphocytes as part of the lymphoid microenvironment. After isolation from human tonsils and expansion in vitro we analyzed the surface phenotype, extracellular matrix components, cytoskeletal products, cytokine production, binding and functional interaction with B lymphocytes of in vitro cultured stromal cells (HTSC) both in resting condition and after activation with tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma. Our results show that HTSC do not express specific myeloid, lymphoid, endothelial or epithelial markers. HTSC express CD54 (ICAM-1), CD49a (VLA-1), CD49b (VLA-2), CD49c (VLA-3), CD49e (VLA-5), CD49f (VLA-6), CD29, CD51, CD44 and produce vinculin, beta-tubulin, alpha-actin, vimentin, fibronectin, laminin and collagen types I, III and IV. Activation of HTSC up-regulated CD54 (ICAM-1) and induced HLA-DR and CD106 (VCAM-1). HTSC constitutively produce interleukin (IL)-6 which is enhanced upon activation with TNF-alpha. IL-8 and granulocyte/macrophage colony-stimulating factor are detected only in the supernatants of activated HTSC. Reverse transcriptase polymerase chain reaction analysis revealed that HTSC display mRNA for IL-1 alpha, leukemia inhibitory factor and IL-7. The adhesion of tonsillar B lymphocytes to activated HTSC is mediated by CD11a/CD18 and CD54. Furthermore, HTSC can induce maximal proliferation of IL-2-activated B lymphocytes cocultured in direct cell-cell contact with HTSC. These results clearly distinguish in vitro cultured HTSC from common fibroblasts and other non-lymphoid elements present in the lymphoid parenchyma, such as follicular dendritic cells, and show that HTSC actively participate in the lymphoid microenvironment. In vitro cultures of HTSC could therefore be a useful model system for detailed analysis of the interactions between stromal cells and lymphocytes under physiological and pathological conditions.
 ...
PMID:In vitro cultured stromal cells from human tonsils display a distinct phenotype and induce B cell adhesion and proliferation. 856 62

We have analysed the expression of interleukin-2 receptor (IL-2R) on a panel of small-cell lung cancer (SCLC) cell lines. None of the 11 SCLC cell lines studied expressed detectable surface IL-2R alpha or beta chains by indirect immunofluorescence. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses indicated that only one out of 11 cell lines expressed detectable IL-2R beta mRNA while two expressed a weak positivity for IL-2R gamma. Five SCLC cell lines were transfected with the plasmid vector RSV.5 neo containing IL-2 cDNA coding sequence. Stable transfectants secreted biologically active IL-2 (ranging from 25 to 100 U ml-1 in the culture supernatant). IL-2 transfection did not produce significant modifications in the expression of surface molecules such as IL-2R alpha and beta chains, intercellular adhesion molecule-1 (ICAM-1), CD44, HLA class I and II or in IL-2R beta or gamma mRNA. More importantly, IL-2-transfected N592 and NCI H69 cell lines completely lost their tumorigenic potential in nude mice after subcutaneous injection, whereas experimental controls transfected with RSV.5 neo vector only, displayed an in vivo growth pattern identical to that of untransfected cells. In addition, in the N592 model, IL-2-producing N592 inhibited the growth of wild-type N592 injected at the same site, while injection of parental cells on the opposite side did not significantly affect the growth of wild-type tumour cells. Histopathological analysis of the rejection process of IL-2-transfected cells demonstrated the presence of MAC-1+, MAC-3+ macrophages and of RB68C5+ granulocytes, whereas T cells were undetectable and NK cells were scarcely represented. In addition, a reduction of the tumour blood vessels was observed. The possible relevance of these data for the development of vaccination strategies using cytokine-engineered tumour cells in SCLC is discussed.
 ...
PMID:Analysis of IL-2 receptor expression and of the biological effects of IL-2 gene transfection in small-cell lung cancer. 879 83

The membrane glycoprotein CD44 may be associated with aggressive behavior, dissemination, and poor prognosis of a variety of human tumors. In order to extend our knowledge on the expression and significance of CD44 in cells of the dispersed neuroendocrine system we investigated a spectrum of 134 neuroendocrine tumors, including pituitary adenomas, medullary thyroid carcinomas, parathyroid adenomas, pheochromocytomas, neuroblastomas, small-cell lung carcinomas, and bronchopulmonary, pancreatic, and gastrointestinal neuroendocrine tumors immunohistochemically for CD44 standard and variant exon-encoded gene products (CD44v3, -v4, -v5, -v6, -v9). Furthermore, we compared protein expression with that of CD44 mRNA by reverse-transcriptase PCR and Southern blot hybridization in a subset of tumors. Our results show that CD44 expression is correlated with the "histogenetic origin" of the appropriate neuroendocrine neoplasm. Endoderm-derived tumors generally express 3'-end CD44 variant exon-containing isoforms, whereas neural crest-derived tumors rarely are positive for CD44. Furthermore, we provide evidence that CD44 expression is not correlated with metastatic disease or a particular hormonal phenotype but exhibits an association with the degree of cellular differentiation. Thus, CD44 is not useful as marker for malignancy or prognosis. The number of patients with clinical follow-up data in our study was too small to allow definite conclusions about a possible correlation between CD44 expression and prognosis. But CD44 may help to better classify neoplasms with an unclear neuroendocrine phenotype.
 ...
PMID:CD44 isoform expression in the diffuse neuroendocrine system. II. Benign and malignant tumors. 898 43

Hyaluronan, a macromolecular carbohydrate polymer of the extracellular matrix is prominent early in embryogenesis, coinciding with rapid tissue growth. CD44, the predominant receptor for hyaluronan on vertebrate cells, is a variably expressed transmembrane glycoprotein. Mouse anterior prostate glands obtained at various postnatal time points were examined for the expression of hyaluronan and CD44. Reverse transcriptase polymerase chain reaction analysis was used to map the temporal regulation of specific CD44 variant isoforms. In each age group, hyaluronan was localized exclusively in the stromal matrix. Hyaluronan was greatly reduced in the later ages and was entirely absent around the developmentally quiescent proximal regions of the ducts. Early in prostate development, CD44 was prominent in the mesenchyme. However, in the later phases, CD44 expression became associated with membranes of epithelial cells. The role of hyaluronan-CD44 interactions in ductal branching morphogenesis was studied by serum-free organ culture of mouse anterior prostate. In the presence of optimal levels of testosterone, the organs underwent ductal branching morphogenesis. Treatment with either neutralizing anti-CD44 antibodies, hyaluronan hexasaccharides or the enzyme hyaluronidase inhibited androgen-stimulated ductal branching morphogenesis. These results are suggestive of the significant role played by hyaluronan-CD44 interactions in mediating androgen-induced prostatic growth and morphogenesis.
 ...
PMID:Hyaluronan is a prerequisite for ductal branching morphogenesis. 937 96

Despite recent extensive immunohistochemical studies, the expression patterns of CD44 in testicular germ cell tumors are still controversial. In the present study, we investigated the CD44 gene expression in 40 specimens including 18 seminomas, 16 nonseminomatous germ cell tumors (NSGCT), and 6 normal testes by reverse transcriptase-polymerase chain reaction and Western blotting. Reverse transcriptase-polymerase chain reaction analysis revealed that the standard CD44 isoform (CD44s) was expressed in all of the specimens, whereas the variant CD44 isoforms were highly expressed in NSGCTs but barely detectable in seminomas and normal testes. In addition, we confirmed by direct DNA sequence analysis that the predominantly expressed variant isoform in NSGCTs was CD44v8-10. In germ cell tumors, these results were paralleled in Western blot analysis; that is, CD44s protein was expressed in all of the tumor specimens, whereas high molecular weight variant isoforms were expressed only in NSGCTs. However, at the protein level, no detectable CD44 was expressed in normal testes. These findings show that the combined assessment of CD44 expression patterns at both the RNA and protein levels enables us to distinguish among seminoma, NSGCT, and normal testis specimens; hence, it could serve as a useful practical adjunct to conventional diagnostic methods for testicular germ cell tumors.
 ...
PMID:Expression patterns of CD44 adhesion molecule in testicular germ cell tumors and normal testes. 958 83

Total parenteral nutrition (TPN) may cause increased rates of bacterial translocation (BT), possibly due to a loss of epithelial integrity. Cultured epithelial cells have been shown to lose tight junction integrity with interferon gamma (INF-gamma) an action which may be blocked by transforming growth factor beta (TGF-beta). Because intraepithelial lymphocytes (IEL) are a rich source of these cytokines in the epithelium, we hypothesized that changes in the IEL, while mice were receiving TPN, may be responsible for the mediation of such cytokine responses. C57BL/6 mice were randomized to a Control group which received intravenous saline and mouse chow, or a TPN group which received intravenous TPN with no oral feeding. At 7 days mice were assessed for BT. Isolated IEL were stained for CD4, CD8, and CD44 (as a marker for memory T-cells) and flow cytometry was performed. mRNA was extracted from remaining IEL for cytokine expression. Reverse transcriptase polymerase chain reaction was performed to detect TGF-beta1 and INF-gamma mRNA expression. Densities were standardized to beta-actin expression. The incidence of BT to mesenteric lymph nodes was 40 and 12.5%, for the TPN and Control groups, respectively. TPN led to statistically significant decreases in the CD4+, CD8-; CD4+, CD8+; and the CD8+, CD44+ IEL subpopulations (P < 0.05). mRNA expression for INF-gamma was increased by 53% (P < 0.05), and TGF-beta1 mRNA expression was decreased by 75% (P = 0.1) in the IEL of TPN mice when compared with Controls. TPN led to significant changes in the IEL. Such alterations of the IEL phenotype and function may be a critical mechanism by which epithelial integrity is lost.
 ...
PMID:Alteration of the intestinal intraepithelial lymphocytes during total parenteral nutrition. 975 21

The adhesion molecule CD44 is a multifunctional, ubiquitously expressed glycoprotein that participates in the process of leukocyte recruitment to sites of inflammation and to their migration through lymphatic tissues. In this study, we have investigated the effect of the proinflammatory cytokine IL-1alpha on CD44 gene expression in the human immortalized endothelial cell line ECV304. Immunoblotting of cell extracts showed constitutive expression of a 85-kDa protein corresponding to the standard form of CD44, which was potently up-regulated following IL-1alpha treatment. Furthermore, IL-1alpha induced expression of v3- and v6-containing isoforms of CD44, which migrated at 110 and 140-180 kDa, respectively. The effect of IL-1alpha on CD44 standard, v3- and v6-containing isoforms was dose and time dependent and was inhibited in the presence of IL-1 receptor antagonist. To elucidate the molecular mechanisms regulating CD44 expression in response to IL-1alpha, we investigated the effect of IL-1alpha on CD44 mRNA expression. Reverse-transcriptase PCR and Northern analysis demonstrated an increase in CD44 mRNA expression indicating a transcriptional mechanism of control by IL-1alpha. Furthermore, IL-1alpha increased expression of a reporter gene under the control of the CD44 promoter (up to -1.75 kb). The effect of IL-1alpha was critically dependent on the site spanning -151 to -701 of the promoter. This effect required the presence of an Egr-1 motif at position -301 within the CD44 promoter since mutation of this site abolished responsiveness. IL-1alpha also induced Egr-1 expression in these cells. These studies therefore identify Egr-1 as a critical transcription factor involved in CD44 induction by IL-1alpha.
 ...
PMID:Characterization of CD44 induction by IL-1: a critical role for Egr-1. 1020 38


1 2 Next >>