Osteoblasts activate the Nrf2 signalling pathway in response to arsenic trioxide treatment.
Arsenic trioxide is used to treat a variety of leukaemia types and causes tumour cell death. However, it is not well known whether arsenic trioxide is toxic to bone osteoblast cells, the precursor cells from which leukaemia cells originate. The aim of this study was to examine the response of osteosarcoma cell line MG63 and primary cultured osteoblasts to arsenic trioxide treatment. After 24h of treatment, arsenic trioxide was more effective at inhibiting cell growth and increasing oxidative stress and DNA damage in MG63 cells than in osteoblasts. In addition, arsenic trioxide arrested cell cycle progression in the G2/M phase, and induced apoptosis in MG63 cells, but not in primary cultured osteoblasts. The results further showed that the expression of transcription factor Nrf2 and its downstream antioxidant effectors, including hemeoxygenase-1, glutathione, and superoxide dismutase, was increased in primary cultured osteoblasts. Additionally, expression of heat shock proteins was also increased. Experiments using inhibitors of antioxidant enzymes in the presence of arsenic trioxide-treated osteoblasts demonstrated that glutathione and superoxide dismutase were responsible for reducing oxidative stress, caspase-3 activity, and apoptosis and that heat shock proteins helped reduce caspase-3 activity. Unexpectedly, there was no apparent effect of the markedly increased hemeoxygenase-1, suggesting that other functions might exist for hemeoxygenase-1. These findings demonstrate that osteosarcoma cells are more sensitive to arsenic trioxide treatment than primary cultured osteoblasts and that primary cultured osteoblasts activate the Nrf2 signalling pathway in response to arsenic trioxide exposure to escape from oxidative damage and apoptosis.
Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Pu-Rong
PR
Chiu
Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Yu-Chen
YC
Hu
Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Bau-Shan
BS
Hsieh
Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Tzu-Ching
TC
Huang
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80756, Taiwan.
Hsiao-Ling
HL
Cheng
Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Li-Wen
LW
Huang
Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan. Electronic address: Chang.KeeLung@msa.hinet.net.
Kee-Lung
KL
Chang
D000970:Antineoplastic Agents / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000009:adverse effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004249:DNA Damage; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D010087:Oxides / Q000009:adverse effects*; D015398:Signal Transduction / Q000187:drug effects*
D000970:Antineoplastic Agents; D001152:Arsenicals; D006360:Heat-Shock Proteins; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D010087:Oxides; D000077237:Arsenic Trioxide
Antioxidant; Arsenic trioxide; Heat shock protein; Nrf2; Osteoblast