Abstract | PURPOSE: METHODS:
Endostatin was conjugated to Cy5.5 monofunctional dye and purified from free dye by gel filtration. LLC, a murine tumor, was implanted in C57BL/6 mice. The tumors were allowed to grow to 350 mm(2), at which point the mice were injected with 100 microg/100 microL endostatin-Cy5.5 and imaged at various points under sedation. Imaging was performed using a lightproof box affixed to a fluorescent microscope mounted with a filter in the NIR bandwidth (absorbance maximum 675 nm and emission maximum 694 nm). Images were captured by a CCD and desktop computer and stored as 16-bit Tiff files. The mice were also serially imaged for uptake into the tumor and washout from the tumor. RESULTS: After intraperitoneal injection, endostatin-Cy5.5 was quickly absorbed, producing a NIR fluorescent image of the tumors at 24 h that persisted through 7 days. However, the signal peaked at 42 h after injection. Control animals included mice containing green fluorescent protein (GFP) under the control of an actin promotor, which expresses GFP in every cell; tumor-free mice injected with endostatin- Cy5.5; mice with tumors that were not injected with endostatin- Cy5.5; and mice with tumors injected with dye alone. In the four sets of control animals, no NIR photon emissions were detected at 24 hours or 5 days. Only the GFP mouse was detected using the GFP filter. Unlike previous analogous studies with 4-N-(S-glutathionylacetyl)amino) phenylarsenoxide (GSAO)- Cy5.5 in which the tumor image faded with time, the endostatin- Cy5.5 NIR signal was emitted from the tumor up to 7 days after injection, the last time point examined. CONCLUSION: The results of this study demonstrated that endostatin covalently bound to Cy5.5 will migrate from a distant intraperitoneal injection site to a tumor. These data indicate that endostatin-Cy5.5 is appropriate for selectively imaging tumors in experimental animals. Furthermore, data suggest that the anti-angiogenic effect of endostatin occurs through a local mechanism of action, within the tumor or tumor vasculature, rather than through a systemic mechanism.
|
Authors | Deborah Citrin, Tamalee Scott, Mary Sproull, Cynthia Menard, Philip J Tofilon, Kevin Camphausen |
Journal | International journal of radiation oncology, biology, physics
(Int J Radiat Oncol Biol Phys)
Vol. 58
Issue 2
Pg. 536-41
(Feb 01 2004)
ISSN: 0360-3016 [Print] United States |
PMID | 14751525
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)
|
Chemical References |
- Angiogenesis Inhibitors
- CY5.5 cyanine dye
- Carbocyanines
- Drug Combinations
- Endostatins
- Fluorescent Dyes
|
Topics |
- Angiogenesis Inhibitors
- Animals
- Carbocyanines
- Cell Line, Tumor
- Drug Combinations
- Endostatins
- Feasibility Studies
- Fluorescent Dyes
- Male
- Mice
- Mice, Inbred BALB C
- Microscopy, Fluorescence
- Neoplasms
(diagnosis)
- Spectroscopy, Near-Infrared
|