In vitro validation of bioluminescent monitoring of disease progression and therapeutic response in leukaemia model animals.
OBJECTIVE
The application of in vivo bioluminescence imaging to non-invasive, quantitative monitoring of tumour models relies on a positive correlation between the intensity of bioluminescence and the tumour burden. We conducted cell culture studies to investigate the relationship between bioluminescent signal intensity and viable cell numbers in murine leukaemia model cells.


METHODS
Interleukin-3 (IL-3)-dependent murine pro-B cell line Ba/F3 was transduced with firefly luciferase to generate cells expressing luciferase stably under the control of a retroviral long terminal repeat. The luciferase-expressing cells were transduced with p190 BCR-ABL to give factor-independent proliferation. The cells were cultured under various conditions, and bioluminescent signal intensity was compared with viable cell numbers and the cell cycle stage.


RESULTS
The Ba/F3 cells showed autonomous growth as well as stable luciferase expression following transduction with both luciferase and p190 BCR-ABL, and in vivo bioluminescence imaging permitted external detection of these cells implanted into mice. The bioluminescence intensities tended to reflect cell proliferation and responses to imatinib in cell culture studies. However, the luminescence per viable cell was influenced by the IL-3 concentration in factor-dependent cells and by the stage of proliferation and imatinib concentration in factor-independent cells, thereby impairing the proportionality between viable cell number and bioluminescent signal intensity. Luminescence per cell tended to vary in association with the fraction of proliferating cells.


CONCLUSIONS
Although in vivo bioluminescence imaging would allow non-invasive monitoring of leukaemia model animals, environmental factors and therapeutic interventions may cause some discrepancies between tumour burden and bioluminescence intensity.
Inoue
Yusuke
Y
Department of Radiology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. inoueys-tky@umin.ac.jp
Tojo
Arinobu
A
Sekine
Rieko
R
Soda
Yasushi
Y
Kobayashi
Seiichiro
S
Nomura
Akiko
A
Izawa
Kiyoko
K
Kitamura
Toshio
T
Okubo
Toshiyuki
T
Ohtomo
Kuni
K
D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D004195:Disease Models, Animal; D018450:Disease Progression; D007938:Leukemia / Q000175:diagnosis* / Q000628:therapy*; D008156:Luciferases; D008163:Luminescent Measurements / Q000379:methods*; D008164:Luminescent Proteins; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D008164:Luminescent Proteins; D008156:Luciferases