Chemiluminescence was detected with the Pierce ECL Western Blotting Substrate (Thermo Scientific, Waltham, MA, Usa) and visualized by the Chemidoc MP Imaging System (Bio-Rad, Hercules, CA, Usa). Antibodies for actin, Bak, cyclin D1, vascular endothelial expansion factor (VEGF), and activating transcription issue three (ATF3) have been purchased from Santa Cruz Biotechnology (Santa Cruz, CA, Usa).