TY - JOUR
T1 - In Vivo Imaging of β-Galactosidase Activity Using Far Red Fluorescent Switch
AU - Tung, Ching Hsuan
AU - Zeng, Qing
AU - Shah, Khalid
AU - Kim, Dong Eog
AU - Schellingerhout, Dawid
AU - Weissleder, Ralph
PY - 2004/3/1
Y1 - 2004/3/1
N2 - β-Galactosidase (β-gal) has been widely used as a transgene reporter enzyme, and several substrates are available for its in vitro detection. The ability to image β-gal expression in living animals would further extend the use of this reporter. Here we show that DDAOG, a conjugate of β-galactoside and 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) (DDAO), is not only a chromogenic β-gal substrate but that the cleavage product has far-red fluorescence properties detectable by imaging. Importantly, the cleavage substrate shows a 50-nm red shift, enabling its specific detection in a background of intact probe, a highly desirable feature for in vivo imaging. Specifically, we show that β-gal-expressing 9L gliomas are readily detectable by red fluorescence imaging in comparison with the native 9L gliomas. We furthermore show that herpes simplex virus amplicon-mediated LacZ gene transfer into tumors can be transiently and thus serially visualized over time. The results indicated that in vivo real-time detection of β-gal activity is possible by fluorescence imaging technology.
AB - β-Galactosidase (β-gal) has been widely used as a transgene reporter enzyme, and several substrates are available for its in vitro detection. The ability to image β-gal expression in living animals would further extend the use of this reporter. Here we show that DDAOG, a conjugate of β-galactoside and 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one) (DDAO), is not only a chromogenic β-gal substrate but that the cleavage product has far-red fluorescence properties detectable by imaging. Importantly, the cleavage substrate shows a 50-nm red shift, enabling its specific detection in a background of intact probe, a highly desirable feature for in vivo imaging. Specifically, we show that β-gal-expressing 9L gliomas are readily detectable by red fluorescence imaging in comparison with the native 9L gliomas. We furthermore show that herpes simplex virus amplicon-mediated LacZ gene transfer into tumors can be transiently and thus serially visualized over time. The results indicated that in vivo real-time detection of β-gal activity is possible by fluorescence imaging technology.
UR - http://www.scopus.com/inward/record.url?scp=1642328231&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=1642328231&partnerID=8YFLogxK
U2 - 10.1158/0008-5472.CAN-03-3226
DO - 10.1158/0008-5472.CAN-03-3226
M3 - Article
C2 - 14996712
AN - SCOPUS:1642328231
SN - 0008-5472
VL - 64
SP - 1579
EP - 1583
JO - Cancer Research
JF - Cancer Research
IS - 5
ER -