Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Long-term expression of a reporter gene has previously been reported in skeletal and cardiac muscles after direct injection of naked plasmid DNA. In this study, we have shown that the direct injection of free plasmid DNA into mouse melanoma BL6 solid tumor can also result in a high level of transfection. THe average amount of chloramphenicol acetyltransferase (CAT) expressed by injecting 30 micrograms plasmid DNA containing a CAT gene into a single BL6 tumor was 1.9 +/- 1.0 ng, which is comparable to that reported in the skeletal muscle. Cationic liposomes, Lipofectamine and DC-chol/DOPE, inhibited gene expression in a dose-dependent manner. Transgene expression by free DNA persisted for at least 10 days. The size of tumor did not seem to affect the gene expression, but proper choice of a diluent solution for DNA was an important factor. Genes driven by the CMV promoter were expressed much more efficiently than genes driven by the SV40 or T7 promoter. Optimal dosage of injected DNA was from 30 to 70 micrograms per tumor. Other mouse melanomas, human melanomas and cervical carcinomas are also able to express directly injected plasmid DNA, but the transfection efficiency is lower than the BL6 tumor. Direct injection of free plasmid DNA is a simple and effective approach and might be a potential method for cancer gene therapy.
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PMID:Direct gene transfer to mouse melanoma by intratumor injection of free DNA. 878 4

DR-nm23 cDNA was cloned recently by differential screening of a cDNA library derived from chronic myelogenous leukemia-blast crisis primary cells. It is highly homologous to the putative metastasis suppressor nm23-H1 gene and the closely related nm23-H2 gene. When overexpressed in the myeloid precursor 32Dcl3 cell line, it inhibited granulocyte colony-stimulating factor-stimulated granulocytic differentiation and induced apoptosis. We have now found that the expression of DR-nm23 is not restricted to hematopoietic cells but is also detected in an array of solid tumor cell lines, including carcinoma of the breast, colon, and prostate, as well as the glioblastoma cell line T98G. We have also isolated both the gene and its 5'-flanking region and found that DR-nm23 localizes on chromosome 16q13. The gene consists of six exons and five introns. When fused in-frame to the nucleotide sequence for the green fluorescent protein and transfected in SAOS-2 cells, it generates a protein of the predicted size that localizes to the cytoplasm. The 5'-flanking region of DR-nm23 does not contain a canonical TATA box or a CAAT box, but it is G+C rich and contains two binding sites for the developmentally regulated transcription factor activator protein 2 (AP-2). Transient expression assays of DR-nm23 promoter-chloramphenicol acetyltransferase constructs demonstrated that the segment from nucleotides -1028 to +123 has the highest activity in hematopoietic K562 cells and in TK-ts13 hamster fibroblasts. Moreover, AP-2 induced a 3-fold transactivation of the DR-nm23 5'-flanking segment from nucleotides -1676 to +123 and interacted specifically with oligomers containing putative AP-2 binding sites (-936 to -909, and -548 to -519) as indicated by electrophoretic mobility shift assay. Furthermore, nuclear run-on assays from high and low DR-nm23-expressing cells (K562 and CCRF-CEM, respectively) revealed similar transcription rates. Therefore, the regulation of the DR-nm23 gene expression might involve other mechanisms occurring at posttranscriptional and/or translational levels.
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PMID:Gene structure, promoter activity, and chromosomal location of the DR-nm23 gene, a related member of the nm23 gene family. 906 90

Cationic liposomes are commonly used for transfection of plasmids into mammalian cells, while microspheres have been traditionally used for selective delivery of anticancer agents into tumor vasculature. We have developed a novel vector, comprised of cationic liposomes electrostatically bound to ion-exchange microspheres (termed 'microplex') for targeted gene therapy of solid tumors. The delivery modes tested in a rat solid tumor model were free plasmids, plasmids bound to microspheres, to liposomes, or to the combination vector. The greatest amount of chloramphenicol acetyltransferase (CAT) reporter gene expression in tumors was achieved using the microplex vector; 3.4-fold compared with free, and 1.8-fold compared with both microspherical and liposomal deliveries (p < 0.01). Tumor-to-normal kidney tissue CAT expression ratios were as follows: free 1.9:1; microspherical 3.7:1; liposomal 1.4:1 and microplexical 2.7:1. Expression between the two types of tissues was significantly different (p < 0.01) for all delivery modes. Microspheres targeted the plasmids to the tumors, while the action of cationic liposomes on cellular membranes allowed more plasmids to breach the cell membrane. This study has proven that the novel microplex vector is capable of selective delivery of genes to tumors and has the potential to target genes in clinical trials.
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PMID:A microsphere-liposome (microplex) vector for targeted gene therapy of cancer. II. In vivo biodistribution study in a solid tumor model. 1089 15