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)

Nonylphenol (NP) is the final biodegradation product of nonylphenol polyethoxylates, which are widely used as surfactants in domestic and industrial products. NP has been reported to have estrogenic activity and shown to have potential reproductive toxicity. However, its influence on immune system function remains unclear. In this study, to determine the immunological effects of NP, the effects of NP on apoptosis and Fas/FasL gene expression in rat thymocyte in vitro were investigated. Thymocytes were treated with NP 0.1, 1, and 10 ppm, respectively. Viable cell numbers were determined by MTT assay. Apoptotic cells were identified by DNA fragment analysis. A semi-quantitative reverse transcriptase-polymerase chain reaction method was used to analyze Fas and FasL mRNA levels. Fas and FasL protein expression was evaluated by flow cytometry. The results showed that NP decreased the cellularity; induced apoptotic death and enhanced the expression of Fas and FasL mRNA as well as proteins in thymocytes. These findings suggest that NP may induce apoptosis by altering the expression of Fas and FasL in thymocytes so as to affect the immune system function.
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PMID:Nonylphenol-induced thymocyte apoptosis is related to Fas/FasL pathway. 1602 79

The murine embryonal teratocarcinoma cell line, P19, was genetically manipulated in order to provide preliminary information on compounds that induce differentiation. Without chemical induction, P19 cells remain in an undifferentiated state, but can be induced to differentiate into specific cell types. For example, dimethyl sulphoxide (DMSO) induces cardiac and skeletal muscle differentiation, whereas retinoic acid stimulates neuronal differentiation. P19 cells were transfected with a construct containing a segment of the murineTert (mTert) promoter sequence combined with the green fluorescent protein (GFP) gene, which acts as a reporter gene. mTert expression, the reverse transcriptase component of murine telomerase, is closely linked to telomerase activity and is down-regulated during differentiation. Three retinoids and DMSO induced the differentiation of P19 cells, which was determined by a reduction in mTert_GFP expression, detected by flow cytometry and confocal microscopy as independent methods of detection. A test substance, ethanol, and a control substance, saccharin, did not cause a decrease in mTert_GFP expression. In addition, it could be demonstrated that the mTert_GFP test detects developmentally relevant effects at non-cytotoxic concentrations. The ID50 values derived for the reduction of mTert_GFP expression were lower than the IC50 values detected with the MTT test, by a factor of 21.4 for all-trans retinoic acid, 12.7 for 9-cis retinoic acid, 29.6 for 13-cis retinoic acid, and 8.7 for DMSO. In comparison to the IC50 value for the P19 cell line, a similar IC50 value was obtained with 3T3 cells for ethanol, but there was a 2-fold increase for DMSO. The retinoids were not cytotoxic to 3T3 cells at the concentrations tested. This newly developed test is capable of detecting differentiation-inducing compounds at non-cytotoxic concentrations within 4 days. It offers a method for detecting chemicals with specific toxicological mechanisms, such as the retinoids, which could provide additional information in embryotoxicity testing as different promoters could be employed. Here, we report the use of this novel test system for the successful analysis of DMSO and three retinoids with different in vivo teratogenic potentials.
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PMID:The detection of differentiation-inducing chemicals by using green fluorescent protein expression in genetically engineered teratocarcinoma cells. 1618 Sep 84

Cisplatin (CDDP) is a widely used potent chemotherapeutic agent for many malignancies. However, the mechanism of resistance to CDDP remains unclear. To investigate the molecular mechanism, we established a CDDP-resistant cell line (H-1R) from a CDDP-sensitive cell line (H-1) which was derived from moderately differentiated squamous cell carcinoma of the lower gingiva. The 3-(3,4-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay indicated that H-1R had a 10-fold greater resistance to CDDP than H-1. When we compared gene expression levels in the cell lines using an in-house cDNA microarray, which represented 2,201 genes originating from normal oral tissue, primary oral cancer, and oral cancer cell lines, 12 genes showing elevated mRNA expression in H-1R compared with H-1 were identified. Among them, the up-regulated expression of ATP-binding cassette transporter genes (MDR1, MRP1, and MRP2), CD55, and PGK1 and down-regulated expression of Caveolin 1 were further confirmed by semiquantitative reverse transcriptase-polymerase chain reaction (PCR) or real-time PCR. Our results suggest that H-1 and H-1R cell lines could be useful for elucidating the candidate genes responsible for CDDP resistance, including the genes found in this study.
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PMID:Establishment and characterization of a cisplatin-resistant oral squamous cell carcinoma cell line, H-1R. 1621 Dec 97

To investigate effects of docosahexaenoic acid (DHA) on proliferation and differentiation of rat adipocytes and to elucidate its potential mechanism, rat's primary preadipocytes in vitro were cultured. Treated adipocytes with 0 micromol/L (control group), 40 micromol/L (lower dose group) and 160 micromol/L (higher dose group) DHA. Cell living rations and proliferation were analyzed by trypan blue exclusion and MTT assay. The degree of adipogenesis and differentiation were measured by Oil Red O staining extraction assay and the expression of peroxisome proliferation activated receptor-gamma2 (PPARgamma2) mRNA were detected by reverse transcriptase-polymerase chain reaction (RT-PCR). It was demonstrated that cells living ration and the optical density (OD) of MTT were all decreased, especially treated by 160 micromol/L DHA at 60 (72 hours (P < 0.05). The OD of Oil Red O staining and the expression of PPARgamma2 mRNA were all decreased after treated by 160 micromol/L DHA (P < 0.01). It can be concluded that DHA can inhibite proliferation and differentiation of adipocytes in some degree. Higher dose of DHA can markedly decrease adipogenesis and prevent differentiation of adipocytes, which may be in part associated with its effect on decreasing the expression of PPARgamma2 mRNA.
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PMID:[Effects of docosahexaenoic acid on rat adipocytes proliferation and differentiation]. 1628 32

Glutamine (Gln), a conditionally essential amino acid, can be a potential enhancer of the heat stress response. And glucose-regulated protein 75(grp75) is a member of the hsp family. To evaluate the effect of glutamine on the expression of grp75, PC12 cell was cultured with DMEM, glucose-free DMEM, DMEM within Gln, and glucose-free DMEM within Gln, and the expression of grp75 was detected by immunocytochemistry and western blot, the mRNA level of grp75 in the cells was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Data indicated that Gln can upregulated the expression of grp75 in PC12 cell line, and the effect is more significantly in PC12 cell which was glucose deprivation than the normal cell. To investigate the effect of Gln on PC12 cells under glucose deprivation, MTT method was used to monitor the cell viability after Gln treatment for the cell under glucose depriving. The experiments results showed that glutamine at a concentration range of 0.2-40 mmol/L significantly enhanced the cell viability in glucose-free DMEM. And the protective effect to grp75 low-expresssion on PC12 cells is markedly decreased.
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PMID:[Effect of glutamine on the expression of grp75 in PC12 cells]. 1636 23

The aquaporins represent a family of transmembrane water channel proteins that play a major role in trans-cellular and transepithelial water movement. Most tumors have been shown to exhibit high vascular permeability and interstitial fluid pressure, but the transport pathways for water within tumors remain unknown. Here, we tested 10 non-small cell lung cancer cell lines of various origins by reverse transcriptase-polymerase chain reaction and Western blot analysis and identified clear expression of aquaporin 1 (AQP1) in seven cell lines. We next examined the distribution of the AQP1 protein in several types of primary lung tumors (16 squamous cell carcinomas, 21 adenocarcinomas, and 7 bronchoalveolar carcinomas) by immunohistochemical staining. AQP1 was overexpressed in 62% (13 of 21) and 75% (6 of 8) of adenocarcinoma and bronchoalveolar carcinoma, respectively, whereas all cases of squamous cell carcinoma and normal lung tissue were negative. Forced expression of full-length AQP1 cDNA in NIH-3T3 cells induced many phenotypic changes characteristic of transformation, including cell proliferation-enhancing activity by the MTT assay and anchorage-independent growth in soft agar. Although further details on the molecular function of AQP1 related to tumorigenesis remain to be elucidated, our results suggest a potential role of AQP1 as a novel therapeutic target for the management of lung cancer.
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PMID:Aquaporin 1 is overexpressed in lung cancer and stimulates NIH-3T3 cell proliferation and anchorage-independent growth. 2290 56

To investigate the relationship between nm23-H1 gene and human chronic myeloblastic leukemia we designed siRNAs which target nm23-H1 gene. According to the principles of designing siRNA, we selected three siRNAs and transfected them into K562 cells by lipofectamine2000. The expression levels of nm23-H1 mRNA were detected by reverse transcriptase polymerase chain reaction after transfection for 24 hours. The expression levels of nm23-H1 protein were assayed by immunocytochemical method after transfection for 48 hours. And after transfection for 24, 48 and 72 hours, cell proliferation was determined by MTT method. Among the three siRNAs, siNM526 can effectively inhibit the expression of nm23-H1 on mRNA and protein levels. The growth of K562 cells was suppressed after transfection of siNM526. These results suggest that low expression level of nm23-H1 in K562 cells inhibited cell proliferation, namely reduced malignant degree of them. Therefore nm23-H1 gene might be a potential target of leukemia treatment.
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PMID:[Analysis of the relationship between nm23-H1 gene and human chronic myeloblastic leukemia using siRNA]. 1675 18

The majority of HIV isolated from infected patients uses CCR5 as a coreceptor (R5-HIV). Although R5-HIV fails to replicate efficiently in human transformed T-cell lines, HIV using CXCR4 (X4-HIV) can replicate well in such cell lines. Therefore, most of screening systems using the T-cell lines detect only X4-HIV replication. Here we report a new assay to monitor the replication of R5- as well as X4-HIV. An MTT assay using CD4-, CXCR4-, and CCR5-transduced human glioma NP-2 cells (NCK45 cells) was established and then compared with the representative assays including multinuclear activation of a galactosidase indicator assay (MAGI assay). The antiviral activities of not only an adsorption inhibitor and reverse transcriptase inhibitors but also a Tat antagonist in the NCK45 cells, were comparable to those obtained from the MTT assay using MT-4 cells or the MAGI assay. However, the activity of protease inhibitors (PIs) was underestimated, even though expressions of major multidrug resistant genes involved in efflux of PIs were comparable in MT-2, NP-2, and NCK45 cells. After cultivation of more than 6 months, NCK45 cells remained susceptible to HIV infection since NCK45 cells consistently expressed CD4, CXCR4, and CCR5. On the other hand, MAGI cells lost the CD4 expression during culture. Thus, this assay system can stably detect the replication of both X4- and R5-HIV, indicating that it should be useful for the evaluation of HIV replication and drug susceptibility.
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PMID:A novel colorimetric assay for CXCR4 and CCR5 tropic human immunodeficiency viruses. 1706 99

This study investigates the expression of human adrenomedullin (ADM) and its receptor-receptor activity modifying protein 2/calcitonin receptor-like receptor (RAMP2/CRLR) mRNA in pheochromocytoma by reverse transcriptase polymerase chain reaction (RT-PCR) and its effect on the proliferation of pheochromocytoma cells by MTT. The mRNA expression of ADM and its receptor RAMP2/CRLR was present in normal adrenal medulla and pheochromocytoma tissues. The mRNA expression of ADM, RAMP2, and CRLR is markedly higher in pheochromocytomas than in normal medulla. ADM inhibits the proliferation of human pheochromocytoma cells and exerts a possible autocrine or paracrine effect in the adrenal.
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PMID:Expression and effect of adrenomedullin in pheochromocytoma. 1710 95

To investigate the effects of Baicalein (BAI) on the proliferation and differentiation of pig preadipocytes, and elucidate its potential mechanism. Primary preadipocytes of pig were cultured in vitro. The morphologic changes of preadipocytes differentiation were observed by Oil Red O staining. Status of cell proliferation was detected by MTT assay. The degree of adipogenesis and differentiation were measured by Oil Red O staining extraction assay. The activity of fatty acid synthase (FAS) was detected by spectrophotometry. The mRNA expression of special peroxisome proliferation activated receptor-gamma2 gene (PPARgamma2) was detected by reverse transcriptase polymerase chain reaction (RT-PCR). When preadipocytes differentiated into adipocytes, the preadipocytes were changed from shuttle shape to oval or round, in which big and small lipid droplets were filled. The proliferation of preadipocytes was inhibited by the treatment of 160-640 micromol/L BAI (P < 0.05). The mRNA expression of PPARgamma2 and FAS activity and the differentiation of preadipocytes was repressed by 40-320 micromol/L BAI treatment (P < 0.05). It is concluded that the proliferation and differentiation of preadipocytes is inhibited by BAI in some degree. The effect of BAI on differentiation of preadipocytes may be resulted from inhibiting the mRNA expression of PPARgamma2 and reducing FAS activity.
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PMID:[Effects of baicalein on the proliferation and differentiation of pig preadipocyte]. 1716 27


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