Abstract
Oxidative stress associated with photodynamic therapy (PDT) is a transcriptional inducer of genes encoding stress proteins, including those belonging to the heat shock protein (hsp) family. The efficiency of PDT to function as a molecular switch by initiating expression of heterologous genes ligated to the human hsp promoter was examined in the present study. Selective and temporal reporter gene expression was documented after PDT in mouse radiation-induced fibrosarcoma cells stably transfected with recombinant vectors containing an hsp promoter ligated to either the lac-z or CAT reporter genes and in transfected radiation-induced fibrosarcoma tumors grown in C3H mice. Hyperthermia treatments were included as a positive control for all experiments. Expression vectors containing either human p53 or tumor necrosis factor (TNF)-alpha cDNA under the control of an hsp promoter were also constructed and evaluated. A p53 null and TNF-alpha-resistant human ovarian carcinoma (SKOV-3) cell line was stably transfected with either the p53 or TNF-alpha constructs. Inducible expression and function of p53 as well as inducible expression, secretion, and biological activity of TNF-alpha were documented after PDT or hyperthermia in transfected SKOV cells. These results demonstrate that PDT-mediated oxidative stress can function as a molecular switch for the selective and temporal expression of heterologous genes in tumor cells containing expression vectors under the control of an hsp promoter.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Cell Survival / drug effects
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Chloramphenicol O-Acetyltransferase / drug effects
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Chloramphenicol O-Acetyltransferase / genetics
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Chloramphenicol O-Acetyltransferase / metabolism
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Dihematoporphyrin Ether / therapeutic use
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Dose-Response Relationship, Drug
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Female
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Gene Expression Regulation, Neoplastic / drug effects
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Heat-Shock Proteins / genetics*
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Heat-Shock Proteins / metabolism
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Humans
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Hyperthermia, Induced
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Mice
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Mice, Inbred C3H
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Oxidative Stress / drug effects
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Oxidative Stress / physiology*
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Photochemotherapy*
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Photosensitizing Agents / therapeutic use*
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Porphyrins / therapeutic use
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Promoter Regions, Genetic / genetics*
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Protein Binding / drug effects
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Recombinant Fusion Proteins / drug effects
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Response Elements
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Temperature
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Tumor Cells, Cultured / cytology
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Tumor Cells, Cultured / drug effects
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Tumor Necrosis Factor-alpha / drug effects
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Tumor Necrosis Factor-alpha / metabolism
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Tumor Suppressor Protein p53 / drug effects
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism
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beta-Galactosidase / drug effects
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beta-Galactosidase / genetics
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beta-Galactosidase / metabolism
Substances
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Heat-Shock Proteins
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Photosensitizing Agents
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Porphyrins
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Recombinant Fusion Proteins
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Tumor Necrosis Factor-alpha
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Tumor Suppressor Protein p53
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Dihematoporphyrin Ether
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Chloramphenicol O-Acetyltransferase
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beta-Galactosidase
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Talaporfin