Cellular Activation of the Self-Quenched Fluorescent Reporter Probe in Tumor Microenvironment
| Autor: | Alexei A. Bogdanov, Jr., Charles P. Lin, Maria Simonova, Lars Matuszewski, Ralph Weissleder |
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| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Neoplasia: An International Journal for Oncology Research, Vol 4, Iss 3, Pp 228-236 (2002) |
| Druh dokumentu: | article |
| ISSN: | 1476-5586 1522-8002 |
| DOI: | 10.1038/sj.neo.7900238 |
| Popis: | The effect of intralysosomal proteolysis of near-infrared fluorescent (NIRF) self-quenched macromolecular probe (PGC-Cy5.5) has been previously reported and used for tumor imaging. Here we demonstrate that proteolysis can be detected noninvasively in vivo at the cellular level. A codetection of GFP fluorescence (using two-photon excitation) and NIRF was performed in tumor-bearing animals injected with PGC-Cy5.5. In vivo microscopy of tumor cells in subdermal tissue layers (up to 160 μm) showed a strong Cy5.5 dequenching effect in GFP-negative cells. This observation was corroborated by flow cytometry, sorting, and reverse transcription polymerase chain reaction analysis of tumor-isolated cells. Both GFP-positive (81% total) and GFP-negative (19% total) populations contained Cy5.5-positive cells. The GFP-negative cells were confirmed to be host mouse cells by the absence of rat cathepsin mRNA signal. The subfraction of GFPnegative cells (2.5-3.0%) had seven times higher NIRF intensity than the majority of GFP-positive or GFPnegative cells (372 and 55 AU, respectively). Highly NIRF-positive, FP-negative cells were CD45-and MAC3-positive. Our results indicate that: 1) intracellular proteolysis can be imaged in vivo at the cellular level using cathepsin-sensitive probes; 2) tumor-recruited cells of hematopoetic origin participate most actively in uptake and degradation of long-circulating macromolecular probes. |
| Databáze: | Directory of Open Access Journals |
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