Bioluminescence imaging of leukemia cell lines in vitro and in mouse xenografts: effects of monoclonal and polyclonal cell populations on intensity and kinetics of photon emission

BACKGROUND We investigated the utility of bioluminescence imaging (BLI) using firefly luciferase in monoclonal and polyclonal populations of leukemia cells in vitro and in vivo. METHODS Monoclonal and polyclonal human lymphoid and myeloid leukemia cell lines transduced with firefly luciferase were used for BLI. RESULTS Kinetics and dynamics of bioluminescence signal were cell line dependent. Luciferase expression decreased significantly over time in polyclonal leukemia cells in vitro. Transplantation of polyclonal luciferase-tagged cells in mice resulted in inconsistent signal intensity. After selection of monoclonal cell populations, luciferase activity was stable, equal kinetic and dynamic of bioluminescence intensity and strong correlation between cell number and light emission in vitro were observed. We obtained an equal development of leukemia burden detected by luciferase activity in NOD-scid-gamma mice after transplantation of monoclonal populations. CONCLUSION The use of monoclonal leukemia cells selected for stable and equal luciferase activity is recommended for experiments in vitro and xenograft mouse models. The findings are highly significant for bioluminescence imaging focused on pre-clinical drug development.