Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.21 (thymidine kinase)
 7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Certain peptides containing high percentage of cationic amino acids are known to efficiently translocate through the cell membrane. This principle was previously exploited for delivery of variety proteins. We had observed that various basic peptides of earlier studies, though not specifically use for gene delivery, contain DNA or RNA binding domains. In the present study, we reported on arginine peptides, which form DNA complexes that efficiently transfect various cell lines. The transfection abilities of the peptides were observed by green fluorescent protein (GFP) and beta-galactosidase gene expression in 293T, HeLa, Jurkat, and COS-7 cells. We found superior transfection activity of arginine peptides compared with commercially available efficient transfection agents. The expression of marker genes induced by arginine peptides was partially inhibited in the presence of heparan sulfate, chondroitin sulfate B and C, or both heparinase III and chondroitinase ABC. The transfection proficiency of these peptides was affected by endosomotropic reagent as well as low temperature (4 degrees C). Finally, we have investigated the potential of arginine peptides as a delivery agent for gene therapy, by attempting to deliver herpes simplex virus thymidine kinase (HSV-TK) gene into tumor cells. HSV-TK transfected tumor cells exhibited sensitivity to the antiviral drug ganciclovir (GCV), leading to cell death. Taken together, these data demonstrate that arginine peptide is proficient for transfection, indicating its potentially benefit to studies in gene therapy and gene delivery in a range of model organisms.
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PMID:Basic peptide system for efficient delivery of foreign genes. 1272 22

Experiments were performed to investigate the impact of didanosine (ddI), lamivudine (3TC), and stavudine (d4T) on cell survival and mutagenicity in two reporter genes, hypoxanthine-guanine phosphoribosyltransferase (HPRT) and thymidine kinase (TK), using a cell cloning assay for assessing the effects of individual nucleoside analogs (NRTIs)/drug combinations in human TK6 B-lymphoblastoid cells. Three-day treatments with 0, 33, 100, or 300 microM ddI, 3TC, or ddI-3TC produced positive trends for increased HPRT and TK mutant frequencies. While dose-related trends were too small to reach significance after treatments with d4T or d4T-3TC, pairwise comparisons with control cells indicated that exposure to 100 microM d4T or d4T-3TC caused significant elevations in HPRT mutants. Measurements of mutagenicity in cells exposed to d4T (or d4T-3TC) were complicated by the cytotoxicity of this NRTI. Enhanced increases in mutagenic responses to combined NRTI treatments, compared with single drug treatments, occurred as additive to synergistic effects in the HPRT gene of cells exposed to 100 microM ddI-3TC or 100 microM d4T-3TC, and in the TK gene of cells exposed to 100 or 300 microM ddI-3TC. Comparisons of these data to mutagenicity studies of other NRTIs in the same system (Meng Q et al. [2000c]: Proc Natl Acad Sci USA 97:12667-126671; Torres SM et al. [2007]: Environ Mol Mutagen) indicate that the relative mutagenic potencies for all drugs tested to date are: AZT-ddI > ddI-3TC > AZT-3TC congruent with AZT-3TC-ABC (abacavir) > AZT >/=ddI > d4T-3TC > 3TC > d4T >/= ABC. These collective data suggest that all NRTIs with antiviral activity against HIV-1 may cause host cell DNA damage and mutations, and impose a cancer risk.
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PMID:Relative mutagenic potencies of several nucleoside analogs, alone or in drug pairs, at the HPRT and TK loci of human TK6 lymphoblastoid cells. 1735 29

One of the gene therapy strategies in oncology is immunization with cancer cells that express various cytokines. We used a thymidine-kinase deficient (cTK-) cell line designated 123IA, which had been derived from HPV16-transformed mouse (C57BL/6) cells MK16/I/III/ABC (MK16). To obtain genetically modified cells, 123IA cells were transfected with bicistronic plasmid vectors carrying the herpes simplex type 1 thymidine kinase (HSV TK) gene and either the gene for the mouse B7.1 (CD80) co-stimulatory molecule or the gene for the monocyte-chemoattractant protein 1 (MCP-1). For control purposes, a plasmid vector carrying only the HSV TK gene was used. The transfected cells were cultivated in medium supplemented with hypoxanthine, aminopterin and thymidine. For comparative purposes we also used B9 cells, which express the granulocyte-macrophage colony stimulation factor (GM-CSF) and had been derived from 123A cells by transduction with the recombinant adeno-associated virus carrying the HSV TK gene and the mouse GM-CSF gene. All of the cell lines isolated were found to be sensitive to minute amounts of ganciclovir, revealing the production of HSV TK, and to express the respective transgenes. When inoculated into 5-week-old female syngeneic mice, cells expressing either GM-CSF or B7.1 were non-oncogenic. On the other hand, nearly all mice inoculated with MCP-1-producing cells developed tumours, though considerably later than animals inoculated with the same dose of the parental MK16 cells. Animals injected with GM-CSF- or B7.1-producing cells were protected against challenge with the parental MK16 cells. When another mouse (C57BL/6) HPV16-transformed oncogenic cell line, TC-1, which differs from the MK16 cells in a number of properties such as MHC class I and B7.1 expression, was used for the challenge, the protective effect was much less pronounced.
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PMID:Live cell vaccines expressing B7.1, monocyte chemoattractant protein 1 and granulocyte-macrophage colony stimulation factor derived from mouse HPV16-transformed cells. 1809 67