title: IER5 promotes irradiation- and cisplatin-induced apoptosis in human hepatocellular carcinoma cells.
abstract: OBJECTIVE
  To elucidate the mechanisms of the immediate-early response gene 5 (IER5) effect on the apoptosis induced by irradiation and cisplatin (CDDP) in human hepatocellular carcinoma (HepG2) cells.
  
  
  METHODS
  We generated IER5 overexpression stable cells (HepG2/IER5) using Lipofectamine 2000 transfection HepG2 cells. Cell apoptosis was induced by irradiation and cisplatin treatments, and cell proliferation (viability) and apoptosis were evaluated by MTT and flow cytometry assays. Protein expression was determined by Western blot.
  
  
  RESULTS
  The growth of the IER5 overexpression cells was significantly inhibited after six days of (60)Co γ-irradiation exposure (p<0.01) compared with the cell growth of vector control cells. Furthermore, the HepG2/IER5 cells were arrested at the G2/M phases. We also found that the expression of phospho-Akt was reduced, and the levels of cleaved caspase-3 and PARP were increased after the treatment of HepG2/IER5 cells with γ-irradiation and cisplatin.
  
  
  CONCLUSIONS
  Our results suggest that the overexpression of IER5 can inhibit cell growth and enhance the cell apoptosis induced by exposure to radiation or cisplatin. The overexpression of IER5 can be utilized as a targeting strategy to improve the outcomes of radiotherapy used for the treatment of patients with liver cancer.
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China.
authors.forename: Chuanjie
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China; Cirrhosis Diagnosis and Treatment Center, 302 Military Hospital of ChinaBeijing 100039, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Hao
authors.affiliation: Institute of Biophysics, The Chinese Academy of Sciences Beijing 100101, China.
authors.forename: Zengqiang
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine Beijing 100850, China.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China.
authors.forename: Huiqing
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Department of Gastroenterology, The Second Hospital of Hebei Medical UniversityShijiazhuang 050000, China; Hebei Key Laboratory of Gastroenterology, Hebei Institute of GastroenterologyShijiazhuang 050000, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine Beijing 100850, China.
authors.forename: Pingkun
authors.initials: P
authors.lastname: Zhou
authors.affiliation: National Institute for Radiological Protection, Chinese Center for Disease Control and PreventionBeijing 100088, China; Key Laboratory of Radiological Protection and Nuclear Emergency, Chinese Center for Disease Control and PreventionBeijing 100088, China.
authors.forename: Kuke
authors.initials: K
authors.lastname: Ding
keywords: IER5; apoptosis; cisplatin; human hepatocellular carcinoma; γ-irradiation