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

---

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

Ginkgolide B, one of the major components of Ginkgo biloba extracts, is a potent platelet-activating factor (PAF) receptor antagonist, which is also regarded as having neuroprotective effects on the CNS. The aim of this research is to observe the effects of Ginkgolide B on the PC12 apoptosis induced by 6-hydroxydopamine (6-OHDA) and to explore whether these effects are related to the changes of intracellular Ca(2+) and Calbindin D28K mRNA in PC12 cells. In the present work, the damage of PC12 cells was induced by 100 microM 6-OHDA. The cells survival rate was examined by MTT assays. The intracellular free calcium concentration in PC12 cells was measured by using the fluorescent Ca(2+) indicator fluo-3/AM. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to determine the expression of Calbindin D28K mRNA in PC12. The data show that the Ginkgolide B inhibited PC12 cells apoptosis induced by 6-OHDA in a dose-dependent manner, and decreased the activity of caspase-3. In addition, Ginkgolide B increased the expression of Calbindin D28K mRNA and inhibited 6-OHDA-induced elevation in the intracellular calcium concentration. Our results showed that the Ginkgolide B inhibited the apoptosis of PC12 induced by 6-OHDA, and the protective effects of Ginkgolide B on PC12 cells are mediated, at least in part, by up-regulating the Calbindin D28K mRNA and by decreasing the intracellular calcium concentration.
...
PMID:Effects of Ginkgolide B on 6-OHDA-induced apoptosis and calcium over load in cultured PC12. 1798 25

Survivin is known to be overexpressed in various human malignancies, including pancreatic cancer, and to cause resistance to radiation and chemotherapy, so the regulation of this molecule could be a new strategy for treating pancreatic cancer. In our study, a short interfering RNA (siRNA) plasmid expression vector against survivin was constructed and transfected into human pancreatic cancer cell lines of Panc-1 and BxPC3. The expression of survivin mRNA and protein among the stable transfected cells and the untransfected cells was detected by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot, respectively. Tumor cell growth in vitro was assessed by trypan blue exclusion. The cell cycle distribution and cell apoptosis were measured by flow cytometry. The cytotoxicity assay was measured by the MTT test. Our results showed that survivin siRNA treatment caused a specific and profound decrease of survivin mRNA and protein that was associated with decreased cell growth, spontaneous apoptosis, and a specific G0/G1 arrest. Furthermore, the suppression of survivin can enhance the chemosensitivity of pancreatic cancer cells to gemcitabine significantly. We suggest that the RNAi against survivin gene strategy would be a potential approach to chemosensitization therapy in human pancreatic cancer.
...
PMID:siRNA directed against survivin enhances pancreatic cancer cell gemcitabine chemosensitivity. 1859 80

CD40, a member of the tumor necrosis factor receptor superfamily, is widely expressed on various cell types. Some studies show that CD40 expression is related to several carcinomas, where its function remains largely unknown. This study investigated the expression of CD40 on colon cancer, and evaluated the effect of recombinant soluble human CD40L (rshCD40L) on colon cell lines. CD40 expression on the primary colon cancer samples was detected by immunohistochemistry. The expression of CD40 on colon cell lines was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and flow cytometry. To examine the effects of rshCD40L, the growth-inhibitory activity of rshCD40L on colon cancer cell was examined by MTT assay and the proportion of apoptotic tumor cells was examined in the TUNEL assay. Results showed that CD40 is expressed in human colon primary tumor. Expression of CD40 was elevated in 3 out of 4 colon cell lines examined by RT-PCR and flow cytometry. CD40 expression could be induced by interferon-gamma (IFN-gamma). CD40 ligand, rshCD40L, significantly inhibited the proliferation of the CD40(+) colon cancer cell lines. The inhibition could also be enhanced by IFN-gamma in HCT116 and SW48 cell lines. In addition, rshCD40L induced apoptosis of the CD40(+) colon cancer cell lines. Theses results suggest that CD40 present in colon cancer, and rshCD40L may be of clinical use to inhibit human colon cancer growth.
...
PMID:Expression of CD40 and growth-inhibitory activity of CD40 ligand in colon cancer ex vivo. 1860 31

Alendronate inhibits osteoclastic activity. However, some studies suggest alendronate also has effects on osteoblast activity. We hypothesized alendronate would enhance osteoblastic differentiation without causing cytotoxicity of the osteoblasts. We evaluated the effect of alendronate on the osteogenic differentiation of mouse mesenchymal stem cells. D1 cells (multipotent mouse mesenchymal stem cells) were cultured in osteogenic differentiation medium for 7 days and then treated with alendronate for 2 days before being subjected to various tests using MTT assays, Alizarin Red, enzyme-linked immunosorbent assay, energy-dispersive xray spectrophotometry, reverse transcriptase-polymerase chain reaction, confocal microscopy, and flow cytometric analysis. D1 cells differentiated into osteoblasts in the presence of osteogenic differentiation medium as confirmed by positive Alizarin Red S staining, increased alkaline phosphatase activity and osteocalcin mRNA expression, a calcium peak by energy-dispersive xray spectrophotometry, and by positive immunofluorescence staining against CD44. Osteogenic differentiation was enhanced after treatment with alendronate as confirmed by Alizarin Red S staining, elevated alkaline phosphatase activity and osteocalcin mRNA expression, a greater calcium peak by energy-dispersive xray spectrophotometry, and by immunofluorescence staining against CD44 by flow cytometric analysis. These data suggest alendronate enhances osteogenic differentiation when treated with mouse mesenchymal stem cells in osteogenic differentiation medium.
...
PMID:Alendronate enhances osteogenic differentiation of bone marrow stromal cells: a preliminary study. 1866 32

To compare the anti-HIV-1 activities of (+/-)-11-demethyl-calanolide A and its mother compound (+/-)-calanolide A in vitro and in vivo, the inhibitory activities of the two compounds on HIV-1 reverse transcriptase (RT) were detected in vitro with isotope 3H assay. The cytotoxicity and inhibition of cytopathic effect (CPE) were studied in HIV-1 IIIB infected MT-4 cell cultures by MTT staining method; Mice were given with the two compounds 100 mg x kg(-1) once intraperitoneally, then the mouse sera taken on 30 min and 60 min after administration were detected for the inhibition of HIV-1 RT in vitro. The data showed that (+/-)-11-demethyl-calanolide A and (+/-)-calanolide A inhibited HIV-1 RT in vitro with 50% inhibitory concentration (IC50) of (3.028 +/- 2.514) micromol x L(-1) and (3.965 +/- 5.235) micromol x L(-1), and also inhibited CPE in HIV-1 IIIB infected MT-4 cell cultures with IC50 of (1.081 +/- 0.337) micromol x L(-1) and (1.297 +/- 0.076) micromol x L(-1), respectively. After intraperitoneal injection of 100 mg x kg(-1) of the two compounds in mice, all the mice sera taken 30 and 60 min afterward inhibited HIV-1 RT in vitro. In comparison with control mice sera, the inhibitory rates of the sera for (+/-)-11 -demethyl-calanolide A were (42.7 +/- 1.5)% at 30 min (P < 0.01) and (32.2 +/- 6.1)% at 60 min (P < 0.05), separately, while the inhibitory rates of the sera for (+/-)-calanolide A were (40.7 +/- 6.3)% at 30 min (P < 0.01) and (29.2 +/- 6.7)% at 60 min. The results suggested that (+/-)-11-demethyl-calanolide A is a new non-nucleoside HIV-1 RT inhibitor, its anti-HIV-1 activities in vitro, in cell cultures and in mice were slightly higher than that of its mother compound (+/-)-calanolide A and warrants further studies.
...
PMID:[Anti-HIV activities of HIV-1 reverse transcriptase inhibitor racemic 11-demethyl-calanolide A]. 1871 30

Increasing evidence indicates that gastrin-releasing peptide (GRP) acts as an autocrine growth factor for brain tumors. However, it remains unclear whether the cAMP/protein kinase A (PKA) signaling pathway plays a role in mediating the mitogenic effects of GRP. We show here that GRP combined with agents that stimulate the cAMP/PKA pathway promotes proliferation of human gliobastoma cells. Treatment with GRP combined with the adenylyl cyclase activator forskolin, the cAMP analog 8-Br-cAMP or the phosphodiesterase type IV inhibitor rolipram increased proliferation of U138-MG cells in vitro measured by MTT assay. None of the compounds had an effect when given alone. GRP receptor (GRPR) mRNA and protein expression in U138-MG cells was detected by reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry. The results suggest that GRP and the GRPR interact with the cAMP/PKA signaling pathway in stimulating cancer cell proliferation.
...
PMID:Stimulation of proliferation of U138-MG glioblastoma cells by gastrin-releasing peptide in combination with agents that enhance cAMP signaling. 1871 51

Hybridoma cells used for the production of monoclonal antibodies are also known to form growth inhibitory substances. Growth inhibitors already described in the literature belong to the class of peptides and proteins likeTGF-ss (Transforming Growth Factor-ss). The endogenous retrovirus particles - a further potential substance producing this kind of effect - are described here. To examine whether the retrovirus particles participated in growth inhibitory effects hybridoma cells were cultivated in continuous perfusion mode by using a special reactor set-up. A rapid increase of the signal in the supernatant which coincided with a decrease of viability could be observed by monitoring the reverse transcriptase-activity during this type of fermentation process. The examination of concentrated and fractionated supernatant from this period showed growth inhibitory effects in the biological assay (MTT-assay). Investigations of respective fractions demonstrated retrovirus particles with reverse transcriptase-activity. Based on RT-PCR data it was shown that only inhibitory fractions contain retrovirus particles which were of E-MuLV and MCF origin.
...
PMID:Endogenous retrovirus particles and their repercussion effects on the growth behaviour of continuous hybridoma cultivation processes. 1900 5

We previously established H-1R cells, a cisplatin (CDDP)-resistant cell line, from H-1 cells, a CDDP-sensitive oral carcinoma cell line. The aim of this study was to identify the molecular mechanism of cross-resistance to antitumor drugs containing a platinum agent in H-1R cells. The 3-(3,4-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and clonogenecity assay indicated that H-1R cells showed strong cross-resistance to carboplatin, nedaplatin and oxaliplatin. The expression status of the copper transporter and organic cation transporters was confirmed by real-time quantitative reverse transcriptase-polymerase chain reaction. The transporters ATP7A, ATP7B, hCtr1, hOCT1 and hOCT2 were up-regulated, whereas hOCT3 was down-regulated. The cellular glutathione level was elevated 2-fold in H-1R cells compared with H-1 cells. Our results suggested that H-1 and H-1R cells may be useful in searching for candidate genes responsible for cross-resistance to platinum derivatives and for further studies to understand the mechanism of platinum resistance.
...
PMID:Cross-resistance of platinum derivatives in H-1R, a cisplatin-resistant cell line. 1914 21

The antiretroviral activities of extracts of Euphorbia hirta were investigated in vitro on the MT4 human T lymphocyte cell line. The cytotoxicities of the extracts were tested by means of the MTT cell proliferation assay, and then the direct effects of the aqueous extract on HIV-1, HIV-2 and SIV(mac251) reverse transcriptase (RT) activity were determined. A dose-dependent inhibition of RT activity was observed for all three viruses. The HIV-1 inhibitory potency of E. hirta was studied further, and the activities of the aqueous and 50% methanolic extracts were compared. The 50% methanolic extract was found to exert a higher antiretroviral effect than that of the aqueous extract. The 50% MeOH extract was subjected to liquid-liquid partition with dichloromethane, ethyl acetate and water. Only the remaining aqueous phase exhibited significant antiviral activity; all the lipophilic extracts appeared to be inactive. After removal of the tannins from the aqueous extract, the viral replication inhibitory effect was markedly decreased, and it was therefore concluded that tannins are most probably responsible for the high antiretroviral activity.
...
PMID:Antiviral activities of extracts of Euphorbia hirta L. against HIV-1, HIV-2 and SIVmac251. 1945 10

This study was undertaken to investigate the in vitro effect of islet labeling with iron oxide nanoparticles for MRI on islet viability, insulin secretion, and gene expression. Isolated rat islets were labeled with Resovist (25-200 microg Fe/mL, a clinically approved MRI contrast agent) in the presence or absence of poly-l-Lysine (PLL, 1.5 microg/mL) for 48 h. The iron content of labeled islets was found to increase in a dose-dependent manner. More than 90% of the islets were labeled with 100 microg Fe/mL. We confirmed the localizations of iron oxide nanoparticles within islet beta-cells by insulin immunostaining. As the concentration of Resovist increased, T(2) values as determined by T(2)-weighted MRI on a 1.5 Tesla MR scanner decreased. Labeling of 100 islets in a medium containing 100 microg Fe/mL of Resovist in the absence of PLL provided sufficient contrast for islet visualization on T(2)-weighted MRI. MTT assays showed that the viability of labeled islets was not different from that of unlabeled islets. No statistical difference was observed between labeled (2.91 +/- 0.36) and unlabeled islets (2.83 +/- 0.61) in terms of the ability to secrete insulin, as determined by the glucose stimulation index. We also evaluated the effect of iron oxide incorporation on the gene expressions in islet cells using RT-PCR (reverse transcriptase PCR). Insulin expression in labeled islets was significantly elevated (1.83 +/- 0.25 fold vs. unlabeled; p = 0.005), but not the expression of somatostatin (1.39 +/- 0.18 fold vs. unlabeled; p = 0.085) or glucagons (1.28 +/- 0.13 fold vs. unlabeled; p = 0.09). Expression of an important transcription factor for insulin gene transcription, BETA2 (beta-cell E-box trans-activator), was increased in labeled islets (1.67 +/- 0.15 fold vs. unlabeled; p = 0.029). The findings of this study indicate that Resovist provides a satisfactory means to image islets and has no deleterious effect on islet function or gene expression.
...
PMID:Magnetic resonance imaging and biological properties of pancreatic islets labeled with iron oxide nanoparticles. 1948 18


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---