title: siRNA targeted for NBS1 enhances heat sensitivity in human anaplastic thyroid carcinoma cells.
abstract: Nijmegen breakage syndrome 1 (NBS1) plays an important role as a key protein in the repair of radiation-induced DNA double strand breaks (DSBs), and the work described here was designed to examine the effect of NBS1 on heat sensitivity for human anaplastic thyroid carcinoma 8305c cells. Cellular heat sensitivity was evaluated with colony formation assays. Apoptosis was detected and quantified with terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) assay and Hoechst33342 staining assay. Heat-induced DSBs were measured with flow cytometry using γH2AX antibodies. The transfection of NBS1-siRNA into cells specifically inhibited the expression of NBS1, and enhanced heat sensitivity and the frequency of apoptosis through caspase pathway. In addition, more frequent γH2AX foci were observed in the NBS1-siRNA transfected cells than in control cells transfected with scrambled siRNA at 24 h after heat treatment with a pan-caspase inhibitor. These results suggest that heat sensitisation might result from NBS1-siRNA mediated suppression of heat-induced DSB repair, indicating that NBS1-siRNA could potentially function as a heat sensitiser for cancer patients.
authors.affiliation: Department of Otorhinolaryngology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan.
authors.forename: Noritomo
authors.initials: N
authors.lastname: Okamoto
authors.forename: Akihisa
authors.initials: A
authors.lastname: Takahashi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Ota
authors.forename: Ken
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Mori
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kondo
authors.forename: Taichi
authors.initials: T
authors.lastname: Noda
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Uemura
authors.forename: Katunari
authors.initials: K
authors.lastname: Yane
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoi
authors.forename: Takeo
authors.initials: T
authors.lastname: Ohnishi
mesh_terms: D017209:Apoptosis; D018797:Cell Cycle Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D006358:Hot Temperature; D006801:Humans; D020287:In Situ Nick-End Labeling; D009687:Nuclear Proteins / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism*; D065646:Thyroid Carcinoma, Anaplastic; D013964:Thyroid Neoplasms / Q000473:pathology
chemical_list: D018797:Cell Cycle Proteins; C112156:NBN protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering