title: Photodynamic therapy-mediated oxidative stress as a molecular switch for the temporal expression of genes ligated to the human heat shock promoter.
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.
authors.affiliation: Clayton Center for Ocular Oncology, Children's Hospital Los Angeles, California 90027, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Luna
authors.forename: A
authors.initials: A
authors.lastname: Ferrario
authors.forename: S
authors.initials: S
authors.lastname: Wong
authors.forename: A M
authors.initials: AM
authors.lastname: Fisher
authors.forename: C J
authors.initials: CJ
authors.lastname: Gomer
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015500:Chloramphenicol O-Acetyltransferase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017323:Dihematoporphyrin Ether / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006979:Hyperthermia, Induced; D051379:Mice; D008809:Mice, Inbred C3H; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D013696:Temperature; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D001616:beta-Galactosidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
chemical_list: D006360:Heat-Shock Proteins; D017319:Photosensitizing Agents; D011166:Porphyrins; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D017323:Dihematoporphyrin Ether; D015500:Chloramphenicol O-Acetyltransferase; D001616:beta-Galactosidase; C053434:Talaporfin