Fig. 1

Irradiation-induced cell death promotes cancer-cell metastasis in vitro. a Annexin V /PI for the apoptosis cancer cell percentage in Panc-1 and SW1990 cells treated with various doses X-ray (0, 4, 8, and 12 Gy). The apoptosis cancer cell increased in a dose-dependent manner. b Irradiated Panc-1 and SW1990 cells stimulated untreated cancer cells’ metastasis in a dose- and time-dependent manner. Varied-dose X-ray-treated (0, 4, 8, and 12 Gy) Panc-1 and SW1990 cells seeded in the lower chamber and untreated Panc-1 and SW1990 cells in the upper chamber co-cultured in the transwell system for the indicated time (6, 12, and 18 h). Imagings were taken by electron microscope. Magnification, × 20. Experiments were repeated three times and the data were expressed as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001