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)

The pluripotent nature and proliferative capacity of embryonic stem cells make them an attractive cell source for tissue engineering. In this study, the poly-L-lysine-coated PLGA microspheres which contain retinoic acid (RA) as an inducer factor were prepared by using a water-in-oil-in-water emulsion/solvent evaporation technique. Then, pluripotent P19 embryonic carcinoma cells were seeded on them for differentiating into neural cells. Size and surface morphology of PLGA microspheres were evaluated by scanning electron microscope (SEM). For in vitro examinations, SEM, MTT assay, immunofluorescent staining, histology and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses were carried out. SEM micrographs of the scaffolds showed a diameter in range of 13-100 microm. Based on the release profiles obtained, the concentration of RA released from microspheres reached 10(-6) to 10(-7) mg/ml. MTT assay showed that the number of cells attached on coated microspheres were more in comparison with uncoated microspheres. Immunoflourescent staining and RT-PCR analyses for MapII, beta-tubulin III, Nestin and Pax6 indicated differentiation of P19 cells into neural cells on all of the samples. Finally, the counting of positive cells showed 80+/-8.8% and 72+/-6.9% of the cells expressed beta-tubulin III on the surface of coated and uncoated RA-loaded PLGA microspheres, respectively, while the 64+/-1.1% (P < 0.05) cells expressed tubulin III in group with soluble.
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PMID:Preparation and surface characterization of poly-L-lysine-coated PLGA microsphere scaffolds containing retinoic acid for nerve tissue engineering: in vitro study. 1952 May 54

Medulloblastoma is the most common brain tumor of childhood. Emerging molecular targets in medulloblastoma include neurotrophin and neuropeptide receptors. In the present study, we have examined the influence of brain-derived neurotrophic factor (BDNF)/TrkB receptor- and gastrin-releasing peptide receptor (GRPR)-mediated signaling on the viability of human medulloblastoma cells. The expression of TrkB and GRPR was confirmed by immunohistochemistry and mRNA for both BDNF and GRPR was detected by reverse transcriptase polymerase chain reaction in Daoy, D283, and ONS76 cells. Treatment with BDNF significantly inhibited the viability of Daoy and D283, but not ONS76 cells, measured with the MTT assay. Neither the GRPR agonists GRP and bombesin nor the GRPR antagonist RC-3095 affected cell viability. Because previous findings have indicated that the viability of glioma cells might be enhanced by GRP when combined with the cAMP phosphodiesterase-4 (PDE4) inhibitor rolipram, we also examined the effects of rolipram alone or combined with GRP on cell viability. Rolipram significantly reduced the viability of all three cell lines, and the inhibitory effect of rolipram in Daoy cells was not modified by cotreatment with GRP. The results suggest that BDNF/TrkB and PDE4, but not the GRPR, regulate the viability of medulloblastoma cells.
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PMID:BDNF and PDE4, but not the GRPR, regulate viability of human medulloblastoma cells. 1964 24

To evaluate the effects of recombinant porcine interleukin-18 (rpIL-18) on the replication of viruses in host cells and proliferation of lymphocytes, porcine IL-18 (pIL-18) isolated from a domestic big-white porcine breed found in the Henan province (HN) was cloned using a reverse transcriptase-PCR. The cloned HN pIL-18 contained an ORF of 579 base pairs encoding a 192-amino-acid precursor protein. The amino acid sequence of HN pIL-18 was compared with all the other pIL-18 amino acid sequences and varied by at least one amino acid to the consensus of all the others available. HN pIL-18 mature protein gene was inserted into a prokaryotic vector pGEX-4T-1 and expressed in Escherichia coli BL21. The expression of glutathione-S-transferase-pIL18 fusion protein was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. The rpIL-18 induced in vitro proliferation of concanavalin-A-stimulated porcine splenocytes, as revealed by the MTT assay. We studied the antiviral activities of the rpIL-18 on the replication of porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV), and porcine parvovirus (PPV) cultured in two homologous cell lines. The results suggested that rpIL-18 can stimulate the proliferation of lymphocytes and inhibit viral pathogens infecting the porcine population.
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PMID:Cloning, in vitro expression, and bioactivity of interleukin-18 isolated from a domestic porcine breed found in Henan. 1973 42

This study was to investigate whether ascorbic acid (AA) at pharmacologic concentration became prooxidant and had the potential to influence the expressions of angiogenic and angiostatic chemokine genes in hepatocellular carcinoma (HCC) cell lines. Influence of low (1 mM) and high (30 mM) pharmacologic concentrations of AA on two HCC cell lines (cell line A, HCC24/KMUH; cell line B, HCC38/KMUH) were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Three angiogenic genes (CCL2, CXCL6, IL8), one angiostatic gene (CXCL10) and two genes related to oxidative stress (SOD2, VNN3) were selected for quantitative RT-PCR study. Both low and high pharmacologic concentrations of AA up-regulated CCL2, CXCL6, IL8, SOD2 and VNN3 genes in cell line A, but down-regulated CCL2 and IL8 genes in cell line B. CXCL6 gene in cell line B was down-regulated by high pharmacologic concentration of AA. CXCL10 gene was up-regulated by low pharmacologic concentration of AA, but was down-regulated by high pharmacologic concentration of AA in both cell lines. Low pharmacologic concentration of AA up-regulated VNN3 gene and high pharmacologic concentration of AA up-regulated SOD2 gene in cell line B. These results indicate that pharmacologic concentration of AA becomes prooxidant to HCC cells and has diverse influence on differential expressions of angiogenic chemokine genes in different HCC cell lines. Differential expressions of CXCL10 gene are determined by the concentrations of AA used. Clinical application of AA in patients with HCC should consider these effects.
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PMID:Pharmacologic concentrations of ascorbic acid cause diverse influence on differential expressions of angiogenic chemokine genes in different hepatocellular carcinoma cell lines. 1993 82

The receptor tyrosine kinases (RTKs), epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor 1-3 (VEGFR1-3), are frequently expressed in gastric cancer and are putative therapeutic targets in this disease. We have investigated the anti-proliferative and chemosensitizing properties of the multitargeted small-molecule RTK inhibitors sunitinib and vandetanib in a panel of 4 human gastric and esophageal cancer cell lines. In the 1st instance, the expression of potential targets of these small-molecule inhibitors was examined by reverse transcriptase-polymerase chain reaction, western blotting, and flow cytometry. EGFR mRNA and protein was detected in all cases, with VEGFR2 expression noted in all but 1 line. Both EGF and VEGF were shown to stimulate tumor cell growth, and both sunitinib and vandetanib were found to be associated with significant dose-dependent inhibition of proliferation and an enhancement of apoptosis, as determined by MTT and propidium iodide/Annexin V labeling assays, respectively. The addition of sunitinib to VEGF-stimulated NCI-N87 cells was associated with a reduction in MAPK phosphorylation (pMAPK) but not Akt phosphorylation (pAkt), whereas the addition of vandetanib was associated with reductions in both VEGF- and EGF-mediated VEGFR2 phosphorylation, pMAPK and pAkt. Co-administration of sunitinib significantly enhanced the sensitivity of MKN-45 cells to cisplatin and irinotecan. In addition, vandetanib synergistically enhanced the sunitinib-associated inhibition of gastric cancer cell growth. In conclusion, these preliminary data confirm the importance of EGFR and VEGFR signaling in gastric cancer and suggest that the simultaneous inhibition of RTK-pathways through sunitinib and vandetanib may provide therapeutic benefit in this disease.
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PMID:Analysis of anti-proliferative and chemosensitizing effects of sunitinib on human esophagogastric cancer cells: Synergistic interaction with vandetanib via inhibition of multi-receptor tyrosine kinase pathways. 2003 26

This study was purposed to investigate the reversal effect of glucosylceramide synthase (GCS) inhibitor D, L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) hydrochloride, on multidrug resistance in K562/A02 cells and its mechanism. The IC(50) (the half maximal inhibitory concentration) of PDMP was measured by MTT method. Cell apoptosis and intracellular daunorubicin (DNR) concentration were detected by flow cytometry. The expression of GCS and mdr1 genes were assayed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot. The results showed that the IC(50) of DNR in K562 and K562/A02 cells were 0.23 +/- 0.02 and 7.15 +/- 0.24 microg/ml respectively. When the concentration of PDMP was equal to or less than 20 micromol/L ( < / = 20 micromol/L), the obviously inhibitory effect on proliferation of K562 and K562/A02 cells was not observed, but both 20 micromol/L and 10 micromol/L PDMP could enhance the sensitivity of K562/A02 cells to DNR (p < 0.01) and the reversal multiples were 2.59 and 1.69 respectively. After treating with 20 micromol/L and 10 micromol/L PDMP for 48 hours, the concentration of DNR in K562/A02 cells increased (p < 0.05) and the apoptotic rate also was elevated (p < 0.01). The expressions of GCS and mdr1 genes were down-regulated at mRNA and protein levels after treating K562/A02 cells with 20 micromol/L PDMP for 48 hours. It is concluded that PDMP can enhance the sensitivity of K562/A02 cells to DNR by increasing cell apoptosis rate and accumulation concentration of DNR in cells, which may be related to down-regulated expressions of GCS and mdr1 genes.
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PMID:[Effect of PDMP, a glucosylceramide synthase inhibitor, on reversion of daunorubicin resistance in human leukemia cell line K562/A02]. 2013 23

Glucocorticoid (GC) hormones, increased in response to stress, can cause neuronal loss. We tested the effect of GC hormone on cell viability of neural SHSY-5Y cells and protective effects of ginsenoside Rb1 and Rg3 on the action of GC. We treated SHSY-5Y cells with increasing concentrations of synthetic GC dexamethasone (DEX; 10, 25, 50, and 100 nM) for 24 and 48 h, and then determined cell viability by using MTT assay. We then treated SHSY-5Y cells with DEX (100 nM) with or without the ginsenosides to examine their preventive effects on the cytotoxicity. To explore the underlying molecular mechanisms, we measured mRNA expression of bax and bcl-2 by using reverse transcriptase real-time PCR. SHSY-5Y cells treated with DEX significantly reduced cell viability as compared with control cells. In the presence of Rb1 or Rg3, DEX-induced cytotoxicity was effectively blocked. DEX considerably increased pro-apoptotic bax mRNA expression as compared with control cells. However, Rb1 and Rg3 completely blocked DEX-mediated up-regulation of bax expression. DEX significantly increased neuronal death in organotypic hippocampal slice cultures of rat brain with enhanced generation of ROS, which was effectively inhibited by ginsenoside Rb1 and Rg3. This suggests a potential role of the ginsenosides to target GC action in the brain.
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PMID:Ginsenoside rb1 and rg3 attenuate glucocorticoid-induced neurotoxicity. 2033 84

Long-chain eicosapentaenoic acid (EPA) is found mainly in marine oils, and has wide ranging biological effects. In this study, we evaluated the effect of nanoemulsion-EPA on the osteogenic differentiation of mouse mesenchymal stem cells (D1 cells). D1 cells were cultured in osteogenic differentiation medium (ODM) for 6 days and treated with nanoemulsion-EPA for 2 days and then subjected to various tests; MTT assays, alizarin red S staining, alkaline phosphatase (ALP) activity determinations, calcium contents analysis, reverse transcriptase-polymerase chain reaction (RT-PCR), confocal microscopy, and flow cytometric analysis. D1 cells were found to differentiate into osteoblasts in the presence of osteogenic differentiation medium, as determined by positive alizarin red S staining, increased alkaline phosphatase activity and calcium contents, osteocalcin, osteopontin and Runx2 mRNA expressions, and by positive immunofluorescence staining against CD44 or CD51. Furthermore, osteogenic differentiation was enhanced when cells were treated with nanoemulsion-EPA, as determined by alizarin red S staining, elevated ALP activity, calcium contents and osteocalcin and Runx2 mRNA expression, and immunofluorescence staining and flow cytometric analysis for CD44. Furthermore, pretreatment with p38 inhibitor prior to nanoemulsion-EPA decreased alizarin red S staining and ALP activity. These findings suggest that nanoemulsion-EPA enhances osteogenic differentiation via the p38 pathway when administered to mouse mesenchymal stem cells in osteogenic differentiation medium.
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PMID:Nanoemulsion-eicosapentaenoic acid enhanced alkaline phosphatase, calcium contents, and surface molecules expression during osteogenesis using mouse multipotent bone marrow stromal cells. 2035 40

The hepatotoxicity induced by valproic acid (VPA) has been described in many clinical studies and the related mechanism has been partly elucidated. The objective of this study is to investigate the hepatotoxicity and its underlying mechanism of valproic acid on human hepatoma carcinoma cell line HepG2. The cell viability was evaluated by 3-(4,5-dimethyltyiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in the medium were detected using spectrophotometry. The gene expressions of cytochrome P450 1 A1 (CYP1A1), ATP-binding cassette transporter G1 (ABCG1) and carnitine palmitoyltransferase 1 (CPT1A), related to lipid transport and fatty acid metabolism, were measured by quantitative real-time reverse transcriptase-PCR. Treatment with valproate sodium obviously decreased the viability of HepG2 cells, accompanied by the increased leakages of ALT, AST and LDH in a dose-dependent manner. Furthermore, the gene expressions of CYP1A1, ABCG1 and CPT1A were almost up-regulated in the treated groups. In conclusion, these data suggest that VPA-induced hepatotoxicity was critically enhanced with the elevation of valproate sodium, which may be correlated with up-regulated gene expressions of CYP1A1, ABCG1 and CPT1A.
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PMID:Participation of lipid transport and fatty acid metabolism in valproate sodium-induced hepatotoxicity in HepG2 cells. 2037 Dec 85

This study was purposed to investigate the expression of RPL36A (ribosomal protein 36a) in the newly diagnosed acute myeloid leukemia (AML) cells and its mechanism at the molecular level. The RPL36A mRNA expression in the newly diagnosed AML cells, U937 cells and normal MNCs was determined by RT-PCR. Small interfering RNA (siRNA) targeting to RPL36A was transfected into U937 cells by Lipofectamine 2000 system. Proliferation, cell cycle, apoptosis of U937 were observed through MTT assay, flow cytometry, acridine orange/ethidium bromide (AO/EB) double staining, TUNEL and Annexin V/FITC respectively. RPL36A mRNA and protein expression levels were detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis respectively. The results showed that RPL36A expression in the newly diagnosed AML cells and U937 cells was significantly upregulated. The average OD value of U937 cells transfected with RPL36A siRNA was significantly lower as compared with 3 control groups. The cell percentage in G2-and S-phase increased, which indicated the inhibition effect of RPL36A siRNA on cell proliferation. Remarkable cell apoptosis in U937 cells treated with RPL36A siRNA was observed by AO/EB, TUNEL analysis and Annexin V/FITC assay; RPL36A mRNA and protein expression level of U937 cells treated with siRNA were significantly declined in a time-dependent manner (r=0.9813 and 0.9537). It is concluded that the RPL36A expression in the AML cells is significantly enhanced and the RPL36A gene may be involved in regulation of cell cycle and cell apoptosis of AML, which promotes proliferation of AML cells and inhibits apoptosis of cells.
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PMID:[Proliferation promotion and apoptotic inhibition effects of ribosomal protein RPL36A small interference RNA on U937 cells]. 2041 65


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