title: Establishment and characterization of GSA-1, a human cell line highly susceptible to apoptosis after free-fall.
abstract: The induction of apoptosis by microgravity and/or gravity-changing stress is considered to be one of the important causes of cell death, although the molecular mechanisms of the apoptotic event remain unclarified. In this study, we established a cell line, GSA-1, from ethyl methanesulfonate-treated human RSa cells. GSA-1 cells were highly susceptible to apoptosis after a free-fall; 24.4% of these cells underwent apoptosis after free-fall, compared with only 6% of the RSa cells. The apoptosis of GSA-1 cells was augmented by ultraviolet (UV, principally 254-nm wavelength) irradiation before free-fall to a greater extents than those in RSa cells. The molecular mechanisms of apoptosis included p53 and Bax proteins; the expression of nuclear p53 and cytoplasmic Bax in GSA-1 cells increased at 4 h after free-fall irrespective of irradiation. In addition, the rate of removal of cyclobutane pyrimidine dimer (CPD) in UV-irradiated GSA-1 cells was higher in cells exposed to free-fall than in those under the 1-G condition. Our results suggested that in GSA-1 cells, free-fall accelerates apoptosis, and that this process is associated with the accumulation of p53 and Bax, as well as CPD removal. Thus, GSA-1 cells should be useful for investigating the mechanism of cellular response, including the induction of apoptosis under gravity-changing stress.
authors.affiliation: Department of Environmental Medicine, Faculty of Education, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Nomura
authors.forename: Jyuni
authors.initials: J
authors.lastname: Himeda
authors.forename: Zheng
authors.initials: Z
authors.lastname: Chen
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sugaya
authors.forename: Shunji
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kita
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ichinose
authors.forename: Nobuo
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects; D002460:Cell Line; D006801:Humans; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects; D014893:Weightlessness / Q000009:adverse effects*; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein