基金We thank Drs Hongbing Shu (Wuhan University, China), Jiandong Li (University of Rochester Medical Center, USA), Andrew Thorbum (University of Colorado Comprehensive Cancer Center, USA) and Andreas Strasser (The Walter and Eliza Hall Institute of Medical Research, Australia) for the generous gifts of the constructs. This work was partially supported by the National Natural Science Foundation of China (Grants 30571687 and 30721063) and the State Key Basic Research Program of China (Grant 2007CB507404).