Bioluminescence imaging (BLI)

For in vivo BLI, the rats were inoculated with luciferase-bearing WB-F344 cells suspended in 100 μl of LN-521-containing substrate, with or without PFT-α added. Luciferase bioluminescence of each rat was detected at 1, 3, 5 and 7 days after transplantation, respectively. On the day of imaging, each rat was intraperitoneally injected with 150 mg/kg of the substrate D-luciferin (Gold Biotechnology, USA) and anesthetized by 1% sodium pentobarbital. Imaging was performed within 15 min after luciferin injection using a Xenogen IVIS three-dimensional small-animal in vivo imaging system and analyzed using Living Image software. The region of interest was selected around each abdomen and the total flux (photos/sec) was calculated. Then the BLI signals was normalized for each rat individually with the total flux of the first time point imaging (day 1, also the Baseline) being 100%. We chose to normalized the data to remove the variable of differences in initial cell distribution and to allow for a direct comparison of how the signal changes over time.