title: Adenovirus-mediated FIR demonstrated TP53-independent cell-killing effect and enhanced antitumor activity of carbon-ion beams.
abstract: Combination therapy of carbon-ion beam with the far upstream element-binding protein (FBP)-interacting repressor, FIR, which interferes with DNA damage repair proteins, was proposed as an approach for esophageal cancer treatment with low side effects regardless of TP53 status. In vivo therapeutic antitumor efficacy of replication-defective adenovirus (E1 and E3 deleted adenovirus serotype 5) encoding human FIR cDNA (Ad-FIR) was demonstrated in the tumor xenograft model of human esophageal squamous cancer cells, TE-2. Bleomycin (BLM) is an anticancer agent that introduces DNA breaks. The authors reported that Ad-FIR involved in the BLM-induced DNA damage repair response and thus applicable for other DNA damaging agents. To examine the effect of Ad-FIR on DNA damage repair, BLM, X-ray and carbon-ion irradiation were used as DNA damaging agents. The biological effects of high linear energy transfer (LET) radiotherapy used with carbon-ion irradiation are more expansive than low-LET conventional radiotherapy, such as X-rays or γ rays. High LET radiotherapy is suitable for the local control of tumors because of its high relative biological effectiveness. Ad-FIR enhanced BLM-induced DNA damage indicated by γH2AX in vitro. BLM treatment increased endogenous nuclear FIR expression in TE-2 cells, and P27Kip1 expression was suppressed by TP53 siRNA and BLM treatment. Further, Ad-FIRΔexon2, a dominant-negative form of FIR that lacks exon2 transcriptional repression domain, decreased Ku86 expression. The combination of Ad-FIR and BLM in TP53 siRNA increased DNA damage. Additionally, Ad-FIR showed synergistic cell toxicity with X-ray in vitro and significantly increased the antitumor efficacy of carbon-ion irradiation in the xenograft mouse model of TE-2 cells (P=0.03, Mann-Whitney's U-test) and was synergistic with the sensitization enhancement ratio (SER) value of 1.15. Therefore, Ad-FIR increased the cell-killing activity of the carbon-ion beam that avoids late-phase severe adverse effects independently of the TP53 status in vitro. Our findings indicated the feasibility of the combination of Ad-FIR with DNA damaging agents for future esophageal cancer treatment.
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba City, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kano
authors.affiliation: Division of Clinical Genetics and Proteomics, Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Chiba City, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Matsushita
authors.affiliation: Division of Clinical Genetics and Proteomics, Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Chiba City, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Rahmutulla
authors.affiliation: Center Hospital, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences (NIRS), Chiba City, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Surgery, School of Medicine, Toho University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shimada
authors.affiliation: Department of Genetics, Hyogo College of Medicine, Hyogo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kubo
authors.affiliation: Department of Biochemistry and Genetics, Chiba University, Graduate School of Medicine, Chuo-ku, Chiba, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hiwasa
authors.affiliation: Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chiba City, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Matsubara
authors.affiliation: Division of Clinical Genetics and Proteomics, Department of Molecular Diagnosis, Graduate School of Medicine, Chiba University, Chiba City, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Nomura
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D001761:Bleomycin / Q000494:pharmacology; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects; D004195:Disease Models, Animal; D004938:Esophageal Neoplasms / Q000188:drug therapy*; D005260:Female; D055785:Gene Knockdown Techniques; D005822:Genetic Vectors; D006367:HeLa Cells; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism; D014965:X-Rays; D023041:Xenograft Model Antitumor Assays
chemical_list: D000072260:RNA Splicing Factors; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; C410595:poly-U binding splicing factor 60KDa; D001761:Bleomycin