Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study aimed to search genes altered in expression after long-term treatment with the angiotensin II type 1 receptor (AT1) antagonist, CV-11974, in volume-overloaded hearts. Arteriovenous shunt was made between the common carotid artery and jugular vein in Japanese White rabbits. Shunt-operated rabbits were randomly treated with CV-11974 or vehicle for 6 weeks, starting 6 weeks after surgery. As controls, sham-operated rabbits were given vehicle. Total RNA was prepared from each left ventricular myocardium. Using differential display, we screened one cDNA encoding human beta-catenin, in which the expression was upregulated after CV-11974 administration in shunt rabbit hearts. Beta-catenin is a molecule that exists in the intercalated disks and also works in cytoplasm as a major component of Wnt signaling. We then examined mRNA expressions of beta-catenin and connexin43 by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The mRNA expressions of beta-catenin and connexin43 were markedly depressed in shunt-operated animals given vehicle compared with sham-operated animals (P < 0.01). These results suggest that downregulation of beta-catenin and connexin43 expression might be involved in the process of ventricular remodeling by volume overload. The RT-PCR also demonstrated that beta-catenin mRNA expression was significantly higher in shunt rabbits treated with CV-11974 than in those given vehicle (P < 0.05). These data suggest that volume overload may downregulate beta-catenin expression by an AT1 receptor-mediated pathway.
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PMID:Long-term treatment with angiotensin II type 1 receptor antagonist, CV-11974, restores beta-catenin mRNA expression in volume-overloaded rabbit hearts. 1243

To identify the genes responsible for carcinogenesis and progression of hepatocellular carcinoma (HCC), we screened differentially expressed genes in several human HCC cell lines. Among these genes, Gpr49 was up-regulated in PLC/PRF/5 and HepG2. Gpr49 is a member of the glycoprotein hormone receptor subfamily, which includes the thyroid-stimulating hormone receptor (TSHR). However, Gpr49 remains to be an orphan G-protein-coupled receptor. By real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) analysis, overexpression (>3-fold increase compared with the corresponding noncancerous liver tissue) of Gpr49 mRNA was observed in 18 of 38 (47%) HCCs compared with corresponding noncancerous livers. Clinicopathologically, overexpression of Gpr49 was frequently observed in HCC with mutation in beta-catenin exon 3 (14 of 16 cases, 87.5%). Moreover, introduction of mutant beta-catenin into mouse hepatocytes in culture caused up-regulation of the Gpr49 mouse homologue. Therefore, Gpr49 is likely to be a target gene activated by Wnt-signaling in HCC. In conclusion, although much is still unknown, Gpr49 may be critically involved in the development of HCCs with beta-catenin mutations and has the potential to be a new therapeutic target in the treatment of HCC.
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PMID:Overexpression of orphan G-protein-coupled receptor, Gpr49, in human hepatocellular carcinomas with beta-catenin mutations. 1260 49

Enhanced expression of (pro)matrix metalloproteinase-9 (MMP-9) is associated with human tumor invasion and/or metastasis. COH cells derived from a highly invasive and metastatic Ewing's sarcoma constitutively express proMMP-9. Transfection of a double stranded RNA that targets the MMP-9 mRNA into COH cells depleted the corresponding mRNA and protein as demonstrated by reverse transcriptase-PCR, enzyme-linked immunosorbent assay, and gelatin zymography. proMMP-9 extinction resulted in the following: (i) decreased spreading on extracellular matrix (fibronectin, laminin, collagen IV)-coated surfaces, (ii) inhibition of migration toward fibronectin, and (iii) induced aggregation, which was specifically disrupted by a function-blocking E-cadherin antibody. MMP-9 knockdown concomitantly resulted in increased levels of surface E-cadherin, redistribution at the plasma membrane of beta-catenin, and its physical association with E-cadherin. Moreover, induction of E-cadherin-mediated adhesion was associated with RhoA activation and changes in paxillin cytoskeleton. Finally, an inhibitor of gelatinolytic activity of pro-MMP9 did not reduce COH cell migration confirming that the enzymatic property of COH MMP-9 was not required for migration toward fibronectin. Overall, our observations define a novel critical role for proMMP-9 in providing a cellular switch between stationary and migratory cell phases.
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PMID:Matrix metalloproteinase-9 silencing by RNA interference triggers the migratory-adhesive switch in Ewing's sarcoma cells. 1284 1

Expression of E1AF/PEA3 (ETV4), an ets family transcription factor, has been implicated in the invasive potential of several cancer cell lines through induction of matrix metalloproteinase (MMP) expression. The aim of this study was to examine E1AF mRNA expression and to determine whether it is correlated with progression of, and/or MMP expression in, human colorectal cancer. Using the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), 100 colorectal cancer tissues were analysed for E1AF mRNA expression. Expression of ER81 (ETV1) and ERM (ETV5), the other two members of the PEA3 subfamily, and Ets-1 and Ets-2 was also analysed. The results were correlated with clinicopathological characteristics and MMP expression. Immunohistochemical analysis and an in vitro invasion assay were also performed. E1AF mRNA expression was detected in 62% of the 100 colorectal cancer tissues, but was undetectable or only faintly detected in adjacent non-tumour tissues. E1AF mRNA was detected in all of the ten liver metastases from colorectal cancers. E1AF expression correlated significantly with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advance in pathological tumour-node-metastasis stage, and recurrence. Patients with E1AF-positive tumours had significantly shorter overall and disease-free survival periods than did those with E1AF-negative tumours (p < 0.0001 and p < 0.0001, respectively). E1AF expression retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors (p = 0.0066 and p = 0.0109, respectively). Among the MMPs analysed, expression of MMP-1 and matrilysin correlated significantly with E1AF expression. In contrast, expression of ER81 and ERM did not correlate with clinicopathological characteristics or the expression of these MMPs. Immunohistochemical expression of E1AF was predominantly observed at the invasive front, where the expression of MMP-1 and matrilysin and nuclear beta-catenin expression were often co-localized. Antisense E1AF-transfected HT-29 colon cancer cells expressed reduced levels of MMP-1 and matrilysin and were less invasive in vitro than neo-transfected HT-29 cells. The results of this study suggest that E1AF, the expression of which is closely correlated with the expression of MMP-1 and matrilysin, plays a key role in the progression of colorectal cancer.
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PMID:Association of ets-related transcriptional factor E1AF expression with tumour progression and overexpression of MMP-1 and matrilysin in human colorectal cancer. 1289 92

Cyclin D1 is a target molecule transcriptionally activated by aberrant beta-catenin in Wnt signalling, while prolyl isomerase Pin1 promotes cyclin D1 overexpression directly or through accumulation of beta-catenin in cancer cells. This study aimed to elucidate whether Pin1 was involved in cyclin D1 overexpression and aberrant beta-catenin in thyroid tumourigenesis by examining 14 follicular adenomas (FAa) and 14 papillary thyroid carcinomas (PTCs). All PTCs displayed cyclin D1 overexpression and strong cytoplasmic beta-catenin and/or decreased membrane beta-catenin expression by immunohistochemistry. Overexpression of cyclin D1 mRNA was observed in 45.5% of FAs and 54.5% of PTCs by TaqMan real-time PCR. Pin1 expression was observed in PTC by immunostaining and was confirmed by reverse transcriptase-PCR. There was a strong correlation between cyclin D1 and Pin1/cytoplasmic/membrane beta-catenin expression (p < 0.001), and between Pin1 and cytoplasmic (p < 0.001)/membrane (p = 0.002) beta-catenin expression in thyroid tumours. Mutation of the beta-catenin gene could not be detected in PTC. Western blot analysis demonstrated high levels of cyclin D1 and beta-catenin as well as Pin1 expression in a human PTC cell line possessing wild-type beta-catenin and APC genes. This study suggests that both cyclin D1 overexpression and aberrant beta-catenin expression are of significance in thyroid tumours. Pin1 expression appears to correlate closely with the level of cyclin D1 and aberrant beta-catenin expression in thyroid tumours such as FA and PTC. Pin1 may be an important factor in regulating cyclin D1 and beta-catenin expression during thyroid carcinogenesis.
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PMID:Cyclin D1 overexpression in thyroid tumours from a radio-contaminated area and its correlation with Pin1 and aberrant beta-catenin expression. 1509 72

Butyrate can promote programmed cell death in a number of tumour cells in vitro. This paper provides evidence that butyrate induces apoptosis in human hepatoma HuH-6 and HepG2 cells but is ineffective in Chang liver cells, an immortalised non-tumour cell line. In both HuH-6 and HepG2 cells, apoptosis appeared after a lag period of approximately 16 h and increased rapidly during the second day of treatment. In particular, the effect was stronger in HuH-6 cells, which were, therefore, chosen for ascertaining the mechanism of butyrate action. In HuH-6 cells, beta-catenin seemed to exert an important protective role against apoptosis, since pretreatment with beta-catenin antisense ODN reduced the content of beta-catenin and anticipated the onset of apoptosis at 8 h of exposure to butyrate. Moreover, in HuH-6 cells, butyrate induced loss of mitochondrial membrane potential, release of cytochrome c from mitochondria, activation of caspase 9 and caspase 3, and degradation of poly(ADP-ribose) polymerase. In addition, during the second day of treatment, beta-catenin, pRb, and cyclins D and E were diminished and the phosphorylated form of pRb disappeared. Also, the content of the anti-apoptotic factor Bcl-XL fell markedly during this period, while that of the pro-apoptotic factor Bcl-Xs increased. These effects were accompanied by an increase in both Bcl-XL and Bcl-Xs mRNA transcripts, as ascertained by reverse transcriptase-polymerase chain reaction. Our results suggest that caspases have a crucial role in butyrate-induced apoptosis. This conclusion is supported by the observation that the inhibitors of caspases, benzyloxy carbonyl-Val-Ala-Asp-fluoromethylketone and benzyloxy carbonyl-Asp-Glu-Val-Asp-fluoromethylketone, prevented apoptosis and the decrease in Bcl-XL, pRb, cyclins and beta-catenin. These effects were most probably responsible for the increased sensitivity of the cells to butyrate-induced apoptosis, which was observed on the second day of treatment.
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PMID:Sodium butyrate induces apoptosis in human hepatoma cells by a mitochondria/caspase pathway, associated with degradation of beta-catenin, pRb and Bcl-XL. 1517 5

Development of normal colon epithelial cells proceeds through a systematic differentiation of cells that emerge from stem cells within the base of colon crypts. Genetic mutations in the adenomatous polyposis coli (APC) gene are thought to cause colon adenoma and carcinoma formation by enhancing colonocyte proliferation and impairing differentiation. We currently have a limited understanding of the cellular mechanisms that promote colonocyte differentiation. Herein, we present evidence supporting a lack of retinoic acid biosynthesis as a mechanism contributing to the development of colon adenomas and carcinomas. Microarray and reverse transcriptase-PCR analyses revealed reduced expression of two retinoid biosynthesis genes: retinol dehydrogenase 5 (RDH5) and retinol dehydrogenase L (RDHL) in colon adenomas and carcinomas as compared with normal colon. Consistent with the adenoma and carcinomas samples, seven colon carcinoma cell lines also lacked expression of RDH5 and RDHL. Assessment of RDH enzymatic activity within these seven cell lines showed poor conversion of retinol into retinoic acid when compared with normal cells such as normal human mammary epithelial cells. Reintroduction of wild type APC into an APC-deficient colon carcinoma cell line (HT29) resulted in increased expression of RDHL without affecting RDH5. APC-mediated induction of RDHL was paralleled by increased production of retinoic acid. Investigations into the mechanism responsible for APC induction of RDHL indicated that beta-catenin fails to repress RDHL. The colon-specific transcription factor CDX2, however, activated an RDHL promoter construct and induced endogenous RDHL. Finally, the induction of RDHL by APC appears dependent on the presence of CDX2. We propose a novel role for APC and CDX2 in controlling retinoic acid biosynthesis and in promoting a retinoid-induced program of colonocyte differentiation.
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PMID:The tumor suppressor adenomatous polyposis coli and caudal related homeodomain protein regulate expression of retinol dehydrogenase L. 1519 67

Expression of matrilysin-2, matrix metalloproteinase (MMP)-26, has been implicated in the progression of several types of human cancer. Matrilysin-2 has been reported to be a physiological and pathological activator of pro-MMP-9. The aim of this study was to examine matrilysin-2 expression and determine whether it is correlated with progression of human esophageal squamous cell carcinoma (ESCC). Semi-quantitative reverse transcriptase-polymerase chain reaction, immunohistochemical analysis, zymography and an in vitro invasion assay were performed. Matrilysin-2 mRNA expression was undetectable or only faintly detected in non-tumor tissues, but its overexpression was detected in 24 of the 50 ESCC tissues. Matrilysin-2 overexpression was significantly correlated with depth of invasion, lymph node metastasis and an advance in pathological tumor node metastasis (pTNM) stage. Sections with immunostaining signals in >10% of carcinoma cells at the invasive front, which were observed in 46 of 100 cases, were judged to be positive for matrilysin-2 expression. Matrilysin-2 expression was significantly correlated with depth of invasion, lymph node and distant metastasis, advance in pTNM stage and recurrence. Expression of matrilysin-2 was significantly correlated with nuclear beta-catenin expression and MMP-9 expression. Patients with matrilysin-2-positive cancer had significantly shorter overall and disease-free survival periods than did those with matrilysin-2-negative cancer. Matrilysin-2 expression retained its significant predictive value for overall and disease-free survival in multivariate analysis. Moreover, patients with concomitant expression of matrilysin-2 and MMP-9 had the worst prognosis. Zymography revealed that matrilysin-2 expression was significantly correlated with expression of active MMP-9 in ESCC tissues. Matrilysin-2-transfected TE-1 ESCC cells showed active MMP-9 activity and were more invasive in vitro compared with mock-transfected TE-1 cells. The results of this study suggest that matrilysin-2, the expression of which is closely correlated with nuclear beta-catenin expression and active MMP-9 activity, plays a key role in the progression of ESCC.
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PMID:Association of matrilysin-2 (MMP-26) expression with tumor progression and activation of MMP-9 in esophageal squamous cell carcinoma. 1533 66

Through their broad differentiation potential, mesenchymal stem cells (MSCs) are candidates for a range of therapeutic applications, but the precise signaling pathways that determine their differentiated fate are not fully understood. Evidence is emerging that developmental signaling cues may be important in regulating stem cell self-renewal and differentiation programs. Here we have identified a consistent expression profile of Wnt signaling molecules in MSCs and provide evidence that an endogenous canonical Wnt pathway functions in these cells. Wnts bind to Frizzled (Fz) receptors and subsequent canonical signaling inhibits glycogen synthase kinase-3beta (GSK-3beta), causing beta-catenin translocation into the nucleus to induce target gene expression. In human MSCs isolated from bone marrow of different donors, we appear to have identified a common Wnt/Fz expression profile using reverse transcriptase polymerase chain reaction (RT-PCR). Associated Wnt signaling components, including low-density lipoprotein receptor-related protein-5 (LRP-5), kremen-1, dickkopf-1 (Dkk-1), secreted Frizzled-related peptide (sFRP)-2, sFRP3, sFRP4, Disheveled (Dvl), GSK-3beta, adenomatous polyposis coli (APC), beta-catenin,T-cell factor (TCF)-1, and TCF-4, were also identified. Nuclear beta-catenin was observed in 30%-40% of MSCs, indicative of endogenous Wnt signaling. Exposure to both Wnt3a and Li+ ions, which promotes canonical Wnt signaling by inhibiting GSK-3beta, reduced phosphorylation of beta-catenin in MSCs and increased beta-catenin nuclear translocation approximately threefold over that of the controls. Our findings indicate that autocrine Wnt signaling operates in primitive MSC populations and supports previous evidence that Wnt signaling regulates mesenchymal lineage specification. The identification of a putative common Wnt/Fz molecular signature in MSCs will contribute to our understanding of the molecular mechanisms that regulate self-renewal and lineage-specific differentiation.
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PMID:Expression profiling and functional analysis of wnt signaling mechanisms in mesenchymal stem cells. 1534 48

Interaction of nuclear beta-catenin and TCF4 is the end point of canonical Wnt signaling, which is believed to trigger the transcription of multiple cancer-associated genes, including CD44. So far, the combined status of beta-catenin and TCF4 and its relevance for lymph node metastasis and CD44 expression have not been well studied in gastric cancers (GCs). To address these issues, we examined 31 GCs, 17 premalignant tissues, 10 noncancerous gastric mucosae, 17 regional lymph node metastases, and 4 human GC cell lines (MGC803, MGC823, AGS, and HGC-27) using immunohistochemical and immunofluorescence staining, reverse transcriptase polymerase chain reaction, and Western blot analysis. Frequent TCF4 up-regulation and nuclear translocation of beta-catenin were found in both primary and metastatic tumors. Standard CD44 was detected in all gastric tissue samples. The frequency of variant CD44 expression increased in parallel with stepwise gastrocarcinogenesis and tumor spread, but the rates of detection did not match that of nuclear beta-catenin and TCF4, especially in the premalignant and noncancerous samples. The data from the 4 cell lines were in accordance with the in vivo findings in terms of beta-catenin nuclear translocation, TCF4 activation, and CD44 expression. Our results suggest an established Wnt signaling pathway in most GCs, a close correlation of beta-catenin/TCF4-mediated signaling with tumor dissemination, and the unlikelihood of a direct effect of activated Wnt signaling on CD44 expression. The influence of beta-catenin-TCF4 interaction on alternative CD44 splicing was not established. These 3 alterations may be regarded as unfavorable features of GC.
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PMID:Nuclear translocations of beta-catenin and TCF4 in gastric cancers correlate with lymph node metastasis but probably not with CD44 expression. 1631 Nov 23


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