title: Silencing of poly(ADP-ribose) glycohydrolase sensitizes lung cancer cells to radiation through the abrogation of DNA damage checkpoint.
abstract: Poly(ADP-ribose) glycohydrolase (PARG) is a major enzyme that plays a role in the degradation of poly(ADP-ribose) (PAR). PARG deficiency reportedly sensitizes cells to the effects of radiation. In lung cancer, however, it has not been fully elucidated. Here, we investigated whether PARG siRNA contributes to an increased radiosensitivity using 8 lung cancer cell lines. Among them, the silencing of PARG induced a radiosensitizing effect in 5 cell lines. Radiation-induced G2/M arrest was largely suppressed by PARG siRNA in PC-14 and A427 cells, which exhibited significantly enhanced radiosensitivity in response to PARG knockdown. On the other hand, a similar effect was not observed in H520 cells, which did not exhibit a radiosensitizing effect. Consistent with a cell cycle analysis, radiation-induced checkpoint signals were not well activated in the PC-14 and A427 cells when treated with PARG siRNA. These results suggest that the increased sensitivity to radiation induced by PARG knockdown occurs through the abrogation of radiation-induced G2/M arrest and checkpoint activation in lung cancer cells. Our findings indicate that PARG could be a potential target for lung cancer treatments when used in combination with radiotherapy.
authors.affiliation: Shien-Lab, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan; Department of Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nakadate
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kodera
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Taro
authors.initials: T
authors.lastname: Tachibana
authors.forename: Tomohide
authors.initials: T
authors.lastname: Tamura
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Koizumi
mesh_terms: D045744:Cell Line, Tumor; D004249:DNA Damage / Q000235:genetics*; D059565:G2 Phase Cell Cycle Checkpoints / Q000235:genetics; D020868:Gene Silencing; D006026:Glycoside Hydrolases / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000532:radiotherapy*; D034741:RNA, Small Interfering / Q000235:genetics; D011836:Radiation Tolerance / Q000235:genetics*
chemical_list: D034741:RNA, Small Interfering; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase
keywords: BER; Checkpoint; DNA damage; DSB; Lung cancer; NAD; NSCLC; PAR; PARG; PARP; Radiation; SCLC; SSB; Sensitization; X-ray repair cross-complementing protein 1; XRCC1; base excision repair; double-strand break; nicotine adenine dinucleotide; non-small cell lung cancer; poly(ADP-ribose); poly(ADP-ribose) glycohydrolase; poly(ADP-ribose) polymerase; single-strand break; small cell lung cancer