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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Choroidal and ciliary body melanomas disseminate exclusively by a hematogenous route because there are no lymphatics inside the eye. Although angiogenesis is an absolute precondition for metastasis in this tumor system, not all morphologic expressions of tumor angiogenesis are associated with metastasis from choroidal and ciliary body melanomas. Specifically, the remodeling of the microcirculation to form vascular networks is very strongly associated with metastasis. Type VI collagen is upregulated in tissue remodeling and the generation of tissue patterns and is either not present in the normal choroid or present at very low levels. This study was designed to investigate the possible expression of type VI collagen in the stroma of choroidal and ciliary body melanomas. Type VI collagen was detected in tissue sections from five primary choroidal melanomas and three melanomas involving the choroid and ciliary body in the subendothelial compartment of the microcirculation and in avascular areas by immunohistochemistry. Melanoma cell lines were established from each of these tumors. Cultured melanoma cells invaded into type I collagen gels and expressed type VI collagen by immunohistochemistry. Using specific primers for human type VI collagen, the expected band size (413 base pairs) was isolated from one of the cell lines by reverse transcriptase PCR. The presence of type VI collagen in the melanoma tumor stroma reflects active remodeling of the uveal extracellular matrix microenvironment by the melanoma cells themselves. Before the formation of the microvasculature, the expression of type VI collagen and of the other matrix components, such as hyaluronan, to which it binds, may erect a scaffold permitting the formation of higher order stromal patterns such as vascular networks. These stromal patterns, which are markers of tumor progression, may be detectable clinically by a specialized form of ultrasonography that detects backscatterers of the same dimension as tissue compartments encircled by vascular loops in networks.
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PMID:Expression of type VI collagen in uveal melanoma: its role in pattern formation and tumor progression. 868 40

Ca(2+)-activated K(+) (K(Ca)) channels have been suggested to play a role in the control of endothelial functions such as regulation of vascular tone and cell proliferation. We established a method for single-cell reverse transcriptase-polymerase chain reaction analysis in combination with the patch-clamp technique to characterize K(Ca) channel expression and function in single endothelial cells (ECs) within the endothelial monolayer of intact human mesenteric arteries (MAs) and in disease states. We tested whether endothelial K(Ca) channel expression and function are altered in MAs obtained from patients with colonic adenocarcinoma (CA) compared with those in MAs from non-cancer patients with inactive diverticulitis. Expression of the intermediate-conductance K(Ca) channel (hIK1) was detected in non-cancer and CA patients. In whole-cell patch-clamp measurements, only ECs expressing hIK1 exhibited corresponding K(Ca) currents, whereas respective K(Ca) currents were missing in hIK1-negative ECs. This heterogeneity of hIK1 expression patterns is indicative of a specialized subset of ECs within the endothelial monolayer. In CA patients, compared with non-cancer patients, a 2.5-fold increase in hIK1-expressing ECs per MA was observed (P:<0.05). However, K(Ca) current densities in hIK1-expressing ECs of both groups were similar. In addition to hIK1, expression of the large-conductance K(Ca) channel (hSlo) was detected in single ECs from CA patients. The increased K(Ca) channel expression in CA patients resulted in a 2. 7-fold increase of bradykinin-induced endothelial hyperpolarization compared with controls (P:<0.05). This increased expression and function of K(Ca) channels might indicate an altered functional state of the endothelium in cancer patients and could play a role in tumor angiogenesis.
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PMID:Expression and function of endothelial Ca(2+)-activated K(+) channels in human mesenteric artery: A single-cell reverse transcriptase-polymerase chain reaction and electrophysiological study in situ. 1098 42

Pituitary tumor transforming gene 1 (PTTG1) recently cloned from human testis is a potent oncogene and is highly expressed in all the tumors analyzed to date. However, primary structure of PTTG1 and the cell types that express PTTG1 in tumors remained undescribed. We have used the reverse transcriptase-polymerase chain reaction technique to clone PTTG1 from ovarian tumors. Nucleotide sequencing of the PTTG1 cDNAs from various ovarian tumors showed identity with that of the human testis PTTG1. To determine the cell types that express PTTG1 in normal and tumor tissues, we performed in situ hybridization using digoxigenin-labeled cRNA as a probe. Our studies revealed a high level of expression of PTTG1 mRNA in both seminomatous and non-seminomatous testicular tumors; epithelial, sex-cord and stromal cell, and germ cell tumors of the ovary; and invasive ductal, ductal in situ and infiltrating ductal carcinoma of the breast. In normal tissues, expression of PTTG1 mRNA was very low or undetectable except in testis, where PTTG1 mRNA was found to be localized to spermatocytes and spermatids. Tumors that expressed high levels of PTTG1 mRNA also exhibited high levels of expression of basic fibroblast growth factor (bFGF), suggesting a correlation between PTTG1 and bFGF expression, and further suggesting that the PTTG1 protein may be involved in tumor angiogenesis and mitogenesis.
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PMID:Molecular cloning of pituitary tumor transforming gene 1 from ovarian tumors and its expression in tumors. 1116 17

The role of thrombospondin (TSP) in tumor angiogenesis and progression remains controversial. The expression of TSP-1 and TSP-2 mRNAs was assessed. Furthermore, TSP association with clinicopathological features, including microvessel count, regarding prognostic significance was examined. Expression of TSP-1 and TSP-2 were assessed by reverse transcriptase-polymerase chain reaction in 18 normal endometrium and 55 endometrial cancer samples. Microvessel counts were determined by immunostaining for factor VIII-related antigen in endometrial cancer specimens. TSP-1 expression of secretory phase endometrium was markedly higher than that of proliferative phase endometrium (p=0.047). Expression of TSP-1 and TSP-2 was detected in 33 (60.0%) and 15 cases (27.3%), respectively, of 55 endometrial cancer samples. TSP-1 expression was significantly higher in tumors recovered from elderly women (p=0.009). TSP-2 expression was significantly higher in malignancies exhibiting cervical and lymph-vascular space involvement (p=0.029 and p=0.009, respectively). Although not statistically significant, microvessel counts were higher in cases displaying increased TSP-1 expression. The microvessel count in patients with TSP-2 expression was markedly higher than that observed in patients lacking TSP-2 expression (p=0.026). Subjects demonstrating TSP-2 mRNA expression displayed significantly poorer prognosis than those lacking TSP-2 mRNA expression (p=0.016). There was no association between TSP-1 mRNA expression and patient outcome. Our findings provide evidence that elevated TSP expression may be associated with an angiogenic phenotype in endometrial cancer. In addition, TSP-2 expression is a marker for poor prognosis in this disease.
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PMID:Thrombospondin-1 and -2 messenger RNA expression in normal and neoplastic endometrial tissues: correlation with angiogenesis and prognosis. 1144 43

Tumor angiogenesis may be an independent prognostic factor for breast cancer survival. However, we can get the angiogenic property of the breast cancer only after the removal of breast tissue. To get this information before surgical resection of the tumor, we evaluated 29 breast carcinoma patients with Tc-99m MIBI scintimammography and power Doppler ultrasound (US) with a microbubble contrast agent preoperatively and compare their results with intratumoral microvessel density (IMD) and reverse transcriptase-polymerase chain reaction (RT-PCR) of VEGF mRNA. IMD was well correlated with VEGF121 (r = 0.220, P = 0.024) and VEGF165 (r = 0.419, P = 0.046) mRNA level of the tumor. Power Doppler US grading of the tumor is well correlated with IMD (r = 0.552, P = 0.033). However, early uptake and washout index calculated from Tc-99m MIBI scintimammography showed no correlation with IMD or VEGF mRNA level, while washout index was inversely correlated with power Doppler US grading (r = -0.945, P = 0.001). In conclusion, the preoperative evaluation of breast cancer with power Doppler US with a microbubble contrast agent could predict tumor angiogenesis. Tc-99m MIBI scintimammography needs further study to use it as an image analysis for angiogenesis.
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PMID:Identification of angiogenesis in primary breast carcinoma according to the image analysis. 1218 72

Tumor angiogenesis requires the production of angiogenic factors by tumor and stromal cells. Macrophages are key effectors of angiogenesis and reported to contribute to tumor angiogenesis in several carcinomas. To investigate interactions between tumor cells and macrophages in angiogenesis, we examined macrophage infiltration, tumor vascularity and expression of monocyte chemoattractant protein (MCP)-1, CC chemokine receptor 2 (CCR2) and vascular endothelial growth factor (VEGF) in 57 archival specimens from patients with esophageal dysplasia (n = 9) and squamous cell carcinomas (n = 48). Expression of MCP-1 mRNA was also examined by reverse transcriptase-polymerase chain reaction (RT-PCR) in 7 esophageal carcinoma cell lines and fresh biopsy specimens from 14 patients. The number of infiltrating macrophages correlated closely with expression of VEGF by tumor cells and with neovascularization. Of the 7 cell lines, 4 (TE-1, 3, 5 and 13) constitutively expressed MCP-1 mRNA. In 9 (64.3%) of the 14 patients, MCP-1 mRNA was expressed at high levels in tumor tissues as compared to normal mucosa. MCP-1 immunoreactivity increased with the depth of tumor invasion (Tis 0%, T1 26.3%, T2, T3 42.1%). Moreover, macrophage and vessel counts were significantly higher in MCP-1-positive tumors than in MCP-1-negative tumors. Normal and dysplastic esophageal squamous epithelium showed no staining or faint cytoplasmic staining of MCP-1. Expression of CCR2 immunoreactivity was detected in the cytoplasm of mononuclear cells but not of vascular endothelial cells. These results suggest that interactions between cancer cells and macrophages are important for tumor angiogenesis. MCP-1 may play a role in progression of human esophageal carcinoma through its role in angiogenesis.
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PMID:Monocyte chemoattractant protein-1 expression correlates with macrophage infiltration and tumor vascularity in human esophageal squamous cell carcinomas. 1239 39

Human thymidine phosphorylase (dThdPase) is an angiogenic factor identical to platelet-derived endothelial cell growth factor (PD-ECGF). Thymidine phosphorylase is also a converting enzyme of the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) to 5-fluorouracil (5-FU) in tumors. To assess the role of dThdPase in targeting chemotherapy, we examined the relationship between the expression of dThdPase and the sensitivity of 5'-DFUR in cancer cell lines, and also examined whether transfection of dThdPase cDNA enhanced the drug-sensitivity to 5'-DFUR with or without angiogenesis in breast cancer cells. Thirteen human cancer cell lines consisting of 4 breast cancer, 6 gastric cancer, and 3 colon cancer cell lines were used. Expression of dThdPase was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). In vitro drug-sensitivity was assessed by MTT assay, and anti-tumor effect in vivo was assessed using nude mouse xenografts. Intratumoral microvessel density was evaluated by immunohistochemical staining to factor VIII related antigen. Transfection of dThdPase cDNA was performed using pcDNA3 expression vector encoding its cDNA by the lipofection method. An inverse relationship between the expression of dThdPase and the IC50 values of 5'-DFUR was observed (p=0.1278, rho=-0.440) in the 13 cancer cell lines. Transfection of dThdPase cDNA into MCF-7 breast cancer cells resulted in an approximately 2.6- and 10-fold increase of the expression of dThdPase mRNA and its enzyme activity, respectively, compared to the control vector alone. The sensitivity to 5'-DFUR in the transfected cells was increased approximately 20-fold compared to the parent cells and control vector alone, and the sensitivity to 5-FU was also somewhat increased. In contrast, the sensitivity to ADM, CDDP, and VP-16 was not different between the transfected and control cells. In nude mice xenografts of the transfected cells, treatment with 5'-DFUR had a significant anti-tumor effect compared to those of the untreated transfected cells and control vector alone treated with 5'-DFUR (p<0.01). Intratumoral microvessel density in the transfected cells was not significantly increased with or without treatment with 5'-DFUR compared to control vector alone. The high expression of dThdPase was correlated with an increase in the sensitivity to 5'-DFUR in gastrointestinal and breast cancer cell lines. The introduction of dThdPase cDNA in breast cancer cells enhanced the sensitivity to 5'-DFUR without an increase of tumor angiogenesis, and targeting chemotherapy of dThdPase may be a good tumor-specific and personalized therapy for improving the poor prognosis of cancer patients who show high expressions of dThdPase.
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PMID:Effects of introduction of dThdPase cDNA on sensitivity to 5'-deoxy-5-fluorouridine and tumor angiogenesis. 1263 76

Nitric oxide (NO) is an important signaling molecule for ischemia, inflammation, angiogenesis, immune response, and cell growth and differentiation. It has recently been shown that increased production of NO within various human cancers may contribute to tumor angiogenesis, tumor growth and metastasis, and tumor-related immune suppression. NO can be produced by several NO synthases (NOS), including inducible synthase (iNOS), which is expressed during cell activation and produces NO in larger quantity and for a longer period of time than non-inducible NOSs. In this study, we examined the expression levels of iNOS mRNA and protein in prostate adenocarcinoma using a paired nonneoplastic and neoplastic primary prostate cell culture system and related prostatectomy specimens. Six pairs of neoplastic and nonneoplastic primary prostate cell cultures were established from radical prostatectomy specimens based on homogeneity of the originating tumor and the nonneoplastic tissue. Radioactive reverse transcriptase polymerase chain reaction and subsequent quantitative analysis of iNOS mRNA were performed on the cultures using beta-actin as an internal control. Immunohistochemical studies with an anti-iNOS monoclonal antibody were performed on the corresponding formalin-fixed paraffin-embedded prostatectomy tissue sections. We observed marked patient-to-patient variation in "normal" levels of iNOS mRNA. However, all six neoplastic cultures showed moderately to markedly higher mRNA levels than did their paired nonneoplastic cultures. In addition, iNOS protein levels were significantly higher in paraffin-embedded prostate cancer tissue sections than in adjacent nonneoplastic tissue. Overexpression of iNOS mRNA and protein levels is present in moderately differentiated prostate adenocarcinoma and may contribute to prostate cancer angiogenesis, tumor growth, and tumor-related immunosuppression.
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PMID:Expression of inducible nitric oxide synthase in paired neoplastic and non-neoplastic primary prostate cell cultures and prostatectomy specimen. 1285 39

Human heparanase has been shown to function in tumor progression, metastatic spread, and tumor angiogenesis. The aim of the present study was to assess heparanase expression in endometrial cancer in correlation with neovascularization and clinicopathological factors. Forty endometrial cancers were obtained from previously untreated patients (median age 55.5, range 33-78 years). The expression of heparanase mRNA was evaluated using a semiquantitative reverse transcriptase-polymerase chain reaction. Tumor angiogenesis was assessed using microvessel counting. The Mann-Whitney U test, one-factor ANOVA test, and Spearman's test were used to determine the relationship between heparanase expression, microvessel density, and clinicopathological parameters. The expression of heparanase mRNA was detected in 20 of 40 (50%) endometrial cancers, and was significantly correlated with FIGO stage IIIc (p=0.0075), the presence of lymph-vascular space involvement (p=0.0041), lymph node metastasis (p=0.0049), and histological tumor grade (p=0.0030). Microvessel density was also associated with FIGO stage IIIc (p=0.027), the presence of lymph-vascular space involvement (p=0.001), lymph node metastasis (p=0.038), ovarian metastasis (p=0.030) and histological tumor grade (p=0.0030). Moreover, we found a strong positive correlation between heparanase expression and microvessel density (r2=0.475, p=0.0001). These results suggest that the expression of heparanase may influence different malignant behaviors in endometrial cancer.
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PMID:Heparanase expression and angiogenesis in endometrial cancer. 1290 90

Hypoxia is a characteristic feature of many human pathologies, including cancer. The sustained proliferation rate of tumor cells leads to alterations of the tumor microenvironment, that progressively becomes more acidic, nutrient-deprived, and hypoxic. The reduced partial pressure of oxygen triggers the onset of an adaptive response, aimed at increasing the local oxygen concentration by several complementary actions. Although directly exposed to the blood stream, endothelial cells lining the vascular lumen in tumors also can be exposed to hypoxia and therefore can contribute to the onset of the adaptive response that leads to tumor angiogenesis. Aiming at getting a detailed insight into the oxygen-dependent regulation of the transcriptional program of vascular endothelial cells and at identifying new relevant markers that may be used as targets for therapeutic intervention in tumor angiogenesis, we have performed a broad-range transcriptomic analysis, using the Affymetrix HG-U133A Gene Chips, of mRNA expression levels in human umbilical cord vein endothelial cells (HUVEC), exposed in vitro to hypoxia for different time periods. The transcriptomic analysis was complemented by a semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of mRNA levels and alternative splicing for some selected extracellular matrix protein genes, and by a proteomic analysis, using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and tandem mass spectrometry for protein separation and identification, of hypoxic and normoxic HUVEC whole-cell lysates and subcellular fractions. Our analysis confirmed previous findings on genes whose expression is regulated by oxygen concentration but also identified new genes (e.g., CXCR4, claudin 3, CD24, tetranectin, Del-1, procollagen lysyl hydroxylase 1 and 2) which are transcriptionally upregulated in hypoxic conditions.
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PMID:Modulation of gene expression by hypoxia in human umbilical cord vein endothelial cells: A transcriptomic and proteomic study. 1517 42


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