tailieunhanh - Báo cáo khoa học: The reactive oxygen species–Src–Stat3 pathway provokes negative feedback inhibition of apoptosis induced by high-fluence low-power laser irradiation

High-fluence low-power laser irradiation (HF-LPLI) can induce apoptosis by triggering mitochondrial oxidative stress. Signal transducer and activa-tor of transcription 3 (Stat3) is an important transcription factor in the modulation of cell proliferation and apoptosis. | ỊFEBS Journal The reactive oxygen species-Src-Stat3 pathway provokes negative feedback inhibition of apoptosis induced by high-fluence low-power laser irradiation Xuegang Sun Shengnan Wu and Da Xing MOE Key Laboratory of Laser Life Science Institute of Laser Life Science College of Biophotonics South China Normal university Guangzhou China Keywords high-fluence low-power laser irradiation negative feedback inhibition reactive oxygen species ROS Src Stat3 Correspondence D. Xing MOE Key Laboratory of Laser Life Science Institute of Laser Life Science College of Biophotonics South China NormalUniversity Guangzhou 510631 China Fax 86 20 85216052 Tel 86 20 85211438 Ext. 8303 E-mail xingda@ Received 12 May 2010 revised 31 August 2010 accepted 14 September 2010 doi High-fluence low-power laser irradiation HF-LPLI can induce apoptosis by triggering mitochondrial oxidative stress. Signal transducer and activator of transcription 3 Stat3 is an important transcription factor in the modulation of cell proliferation and apoptosis. Here using real-time singlecell analysis and western blotting analysis we investigated the changes in activities of Stat3 in COS-7 cells upon HF-LPLI 633 nm 80 and 120 J-cm 2 and the underlying mechanisms involved. We found that Stat3 was significantly activated by HF-LPLI in a time-dependent and dosedependent manner. Stat3 activation attenuated HF-LPLI-induced apoptosis as shown by the fact that both dominant negative Stat3 Y705F and Stat3 small interfering RNA expression enhanced cellular apoptosis induced by HF-LPLI. Moreover we also found that Src kinase was the major positive regulator of Stat3 activation induced by HF-LPLI. Reactive oxygen species ROS generation was essential for Stat3 and Src activation upon HF-LPLI because scavenging of ROS by vitamin C or N-acetylcyste-ine totally abrogated the activation of Stat3 and Src. Taken together these findings show that the ROS-Src-Stat3 pathway mediates a