Geldanamycin-Induced Oxidative Stress Confers Cytoskeletal Reorganization in 9L Rat Brain Tumor Cells

• Main Authors: Chih-Hung Weng, 翁志鴻
• Other Authors: Yiu-Kay Lai
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/87109564402779895177

碩士 === 國立清華大學 === 生命科學系 === 89 === Geldanamycin (GA), a benzoquinone ansamycin, is an antitumor drug which originally described as a tyrosine kinase inhibitor. Herein, we show that exposure of 9L rat brain tumor cells to 5 mM GA for different time durations induces reorganization of cytoskeleton¸ G2/M arrest and apoptosis. In our previous studies, we showed that the intracellular level of reactive oxygen species (ROS) is significantly increased in GA-treated cells. By using confocal microscopy we demonstrated for the first time that after treatment of GA the structure of cytoskeleton in 9L RBT cells was dramatically reorganized and disrupted, and this phenomenon was not reversible by removal of GA and allowed for recovery. Using flow cytometry we showed that after GA treatment significant percentage of cells were arrested in G2/M phase and subdiploid apoptotic status. To investigate whether ROS involved in the aforementioned phenomenon, N-acetylcysteine (NAC), a free radical scavenger, was added prior to GA treatment. We found that pretreatment of NAC could partially prevent GA-induced irreversible reorganization of cytoskeleton and cell arrest into G2/M phase suggesting that the oxidative stress was exerted by GA treatment and that part of the GA-induced ROS occurred upstream of reorganization of the cytoskeleton, cell cycle G2/M arrest and/or apoptosis. We conclude that GA-induced apoptosis, cytoskeletal disruption, and G2/M arrest are, in part, a consequence of a critical GA-induced ROS in 9L RBT cells. ABSTRACT (Chinese)………………………………………………………1 ABSTRACT ……………………………………………………………….2 INTRODUCTION…………………………………………………………..3 MATERIALS AND METHODS……………………………………………….5 RESULTS………………………………………………………………….7 DISCUSSION……………………………………………………………..10 REFERENCES……………………………………………………………..13 FIGURE LEGENDS………………………………………………………..21 FIGURES………………………………………………………………………23