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| The Impact of Hypoxiaon on the Apoptosis and Cell Cycles in Hep-2 Human LKaryngeal Cancer Cell Line Induced by 60Coγ-ray |
| SONG Dong-mei, LIU Yan-mei, WANG Bao-shan, et al |
| Department of Otolaryngology-Head and Neck Surgery, the First Hospital of Hebei Medical University, Shijiazhuang 050031 China |
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Abstract Objective To establish models of Hep-2 laryngeal cancer cell line of different oxygen supplying,investigate the impact of hypoxiaon on the apoptosis and cell cycles in Hep-2 human laryngeal cancer cell line induced by different dosage of γ-ray.Methods The cells were diviced into 2 groups:group A (normoxia)and group B (hypoxia).Both of the two group cells are exposured in different dosage of γ-ray which range from 1Gy to 40Gy.Constructinon group (0Gy)was used.Flow cytometry (FCM)was used to measure the distribution of cell cycles and the protein levels of HIF-1α and to detect cell apoptosis.The protein levels of HIF-1α were also determined by immunohistochemistry.Results 1 Gy-5Gy γ-ray caused G0/G1 cell cycle arrest when 10~40Gy γ-ray caused G2/M cell cycle arrest in human Hep-2 cells in group A.All of the different dosage of γ-ray caused G2/M cell cycle arrest in human Hep-2 cell in group B,then without exposure of γ-ray (0 Gy)could cause G0/G1 cell cycle arrest in group B.The curve of apoptosis rate in group A show a parabola,The peak was 41.56±2.25 at the point of 5 Gy.Apoptotic rate was related to the dosage of γ-ray in a dosage dependent manner.The apoptosis rate in group B were significantly lower than that in group A.The dose difference of γ-ray have no impact on the apoptosis rate in group B.Conclutions Different dosage of γ-ray could cause different cell cycles arrest in the condition of normoxia.There was an important relationship between cell cycle arrest and apoptosis.The descend of the apoptosis rate were related to G2/M cell cycle arrest in the condition of hypoxia and the high expression of HIF-1 maybe one of these reasons.
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Received: 20 July 2009
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