Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10881806 | Cell Biology International | 2005 | 7 Pages |
Abstract
Proteases have received attention as important cellular components responsible for stress response in human cells. However, little is known about the role of proteases in the early steps of cell response after X-ray irradiation. In the present study, we first searched for proteases whose activity levels are changed soon after X-ray irradiation in human RSa cells with a high sensitivity to X-ray cell-killing. RSa cells showed an increased level of fibrinolytic protease activity within 10Â min after irradiation with X-ray (up to 3Â Gy). The induced protease activity was proved to be inhibited by leupeptin. We next examined whether this protease inducibility is related to the X-ray susceptibility of cells. Treatment of RSa cells with leupeptin prior to X-ray irradiation resulted in lowered colony survival and an increased ratio of G2/M-arrested cells and apoptotic cells. These results suggest that leupeptin-sensitive proteases are involved in the resistance of human RSa cells to X-ray cell-killing.
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Authors
Hong-Chang Zhang, Kiyonobu Karata, Kazuyuki Matsushita, Shunji Takahashi, Xiao-Bo Tong, Jun Lu, Chang-Lin Zhu, Shigeru Sugaya, Toshikazu Suzuki, Nobuo Suzuki,