title: Bystander effect in suicide gene therapy is directly proportional to the degree of gap junctional intercellular communication in esophageal cancer.
abstract: Gap junctional intercellular communication (GJIC) has been shown to be involved in the bystander effect through herpes simplex virus thymidine kinase/ganciclovir (HSV-tk/GCV) gene therapy. In this study, we examined the expression of connexins, the components of gap junction, and the degree of GJIC in esophageal cancer cell lines and compared the bystander effect in cells with different capacities of GJIC. We found loss in connexin 26 expression and reduced connexin 43 in esophageal cancer. GJIC capacity varied among cell lines and was dependent on the connexin 43 expression in the cell-cell contact areas. In mixing assay, the extent of the bystander effect was tightly correlated with the degree of GJIC capacity. The effects of retinoic acid and cAMP on the bystander effect were also investigated. Treatment with retinoic acid, but not with cAMP, was associated with augmented bystander killing by increase in GJIC in some esophageal cancer cell lines. Our results indicated that the degree of GJIC was predictive to identify a tumor as suitable for gene therapy with the HSV-tk/GCV system. Also GJIC chemically-enhanced with retinoic acid might be useful to improve response in suicide gene therapy.
authors.affiliation: Department of Surgery, Kurume University School of Medicine, Kurume-shi 830-0011, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Matono
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tanaka
authors.forename: Susumu
authors.initials: S
authors.lastname: Sueyoshi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yamana
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Fujita
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shirouzu
mesh_terms: D015153:Blotting, Western; D024201:Bystander Effect; D002450:Cell Communication; D045744:Cell Line, Tumor; D000072259:Connexin 26; D018031:Connexin 43 / Q000096:biosynthesis; D017630:Connexins / Q000096:biosynthesis; D000242:Cyclic AMP / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000628:therapy*; D015774:Ganciclovir / Q000627:therapeutic use; D017629:Gap Junctions / Q000502:physiology*; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D008856:Microscopy, Fluorescence; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013937:Thymidine Kinase / Q000235:genetics; D013997:Time Factors; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism
chemical_list: D018031:Connexin 43; D017630:Connexins; D012333:RNA, Messenger; D000072259:Connexin 26; D014212:Tretinoin; D000242:Cyclic AMP; D013937:Thymidine Kinase; D015774:Ganciclovir