title: A comprehensive analysis of radiosensitization targets; functional inhibition of DNA methyltransferase 3B radiosensitizes by disrupting DNA damage regulation.
abstract: A comprehensive genome-wide screen of radiosensitization targets in HeLa cells was performed using a shRNA-library/functional cluster analysis and DNMT3B was identified as a candidate target. DNMT3B RNAi increased the sensitivity of HeLa, A549 and HCT116 cells to both γ-irradiation and carbon-ion beam irradiation. DNMT3B RNAi reduced the activation of DNA damage responses induced by γ-irradiation, including HP1β-, γH2AX- and Rad51-foci formation. DNMT3B RNAi impaired damage-dependent H2AX accumulation and showed a reduced level of γH2AX induction after γ-irradiation. DNMT3B interacted with HP1β in non-irradiated conditions, whereas irradiation abrogated the DNMT3B/HP1β complex but induced interaction between DNMT3B and H2AX. Consistent with radiosensitization, TP63, BAX, PUMA and NOXA expression was induced after γ-irradiation in DNMT3B knockdown cells. Together with the observation that H2AX overexpression canceled radiosensitization by DNMT3B RNAi, these results suggest that DNMT3B RNAi induced radiosensitization through impairment of damage-dependent HP1β foci formation and efficient γH2AX-induction mechanisms including H2AX accumulation. Enhanced radiosensitivity by DNMT3B RNAi was also observed in a tumor xenograft model. Taken together, the current study implies that comprehensive screening accompanied by a cluster analysis enabled the identification of radiosensitization targets. Downregulation of DNMT3B, one of the targets identified using this method, radiosensitizes cancer cells by disturbing multiple DNA damage responses.
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Division of Chemotherapy and Translational Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujimori
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Division of Chemotherapy and Translational Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: Sota
authors.initials: S
authors.lastname: Kikuhara
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 103-8501, Japan.
authors.forename: Junhui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Department of Radiation Oncology, Juntendo University Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Hirai
authors.affiliation: Division of Chemotherapy and Translational Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Murakami
authors.affiliation: Open Laboratory/Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Okayasu
authors.affiliation: Division of Genome Stability Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Division of Chemotherapy and Translational Research, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan.|Department of Frontier Life Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1, Sakamoto, Nagasaki 852-8588, Japan.
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Masutani
mesh_terms: D000818:Animals; D059447:Cell Cycle Checkpoints / Q000235:genetics / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D016000:Cluster Analysis; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage; D019175:DNA Methylation; D004195:Disease Models, Animal; D005720:Gamma Rays; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D011836:Radiation Tolerance / Q000235:genetics*; D015398:Signal Transduction / Q000528:radiation effects; D023041:Xenograft Model Antitumor Assays; D000097584:DNA Methyltransferase 3B
chemical_list: D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone; D004248:DNA (Cytosine-5-)-Methyltransferases; D006657:Histones; D034741:RNA, Small Interfering; D000097584:DNA Methyltransferase 3B; C000715593:CBX1 protein, human