title: Treatment of colon cancer cells using the cytosine deaminase/5-fluorocytosine suicide system induces apoptosis, modulation of the proteome, and Hsp90beta phosphorylation.
abstract: The bacterial cytosine deaminase (CD) gene, associated with the 5-fluorocytosine (5FC) prodrug, is one of the most widely used suicide systems in gene therapy. Introduction of the CD gene within a tumor induces, after 5FC treatment of the animal, a local production of 5-fluorouracil resulting in intratumor chemotherapy. Destruction of the gene-modified tumor is then followed by the triggering of an antitumor immune reaction resulting in the regression of distant wild-type metastasis. The global effects of 5FC on colorectal adenocarcinoma cells expressing the CD gene were analyzed using the proteomic method. Application of 5FC induced apoptosis and 19 proteins showed a significant change in 5FC-treated cells compared with control cells. The up-regulated and down-regulated proteins include cytoskeletal proteins, chaperones, and proteins involved in protein synthesis, the antioxidative network, and detoxification. Most of these proteins are involved in resistance to anticancer drugs and resistance to apoptosis. In addition, we show that the heat shock protein Hsp90beta is phosphorylated on serine 254 upon 5FC treatment. Our results suggest that activation of Hsp90beta by phosphorylation might contribute to tumor regression and tumor immunogenicity. Our findings bring new insights into the mechanism of the anticancer effects induced by CD/5FC treatment.
authors.affiliation: Plateforme Protéomique IFR50, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Negroni
authors.forename: Michel
authors.initials: M
authors.lastname: Samson
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Guigonis
authors.forename: Bernard
authors.initials: B
authors.lastname: Rossi
authors.forename: Valérie
authors.initials: V
authors.lastname: Pierrefite-Carle
authors.forename: Christian
authors.initials: C
authors.lastname: Baudoin
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D043525:Cytosine Deaminase / Q000235:genetics*; D015180:Electrophoresis, Gel, Two-Dimensional; D005437:Flucytosine / Q000627:therapeutic use*; D018014:Gene Transfer Techniques; D041722:Genes, Transgenic, Suicide; D015316:Genetic Therapy; D005822:Genetic Vectors; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation; D020543:Proteome / Q000378:metabolism*; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D017304:Annexin A5; D014408:Biomarkers, Tumor; D018841:HSP90 Heat-Shock Proteins; C493165:HSP90AB1 protein, human; D020543:Proteome; D005437:Flucytosine; D043525:Cytosine Deaminase