In vivo imaging of integrin ανβ3 expression using fluorescence-mediated tomography

Abstract

RGD-Cy 5.5 combined with novel tomographic optical imaging methods allows non-invasive imaging of tumour-associated alpha v beta(3) expression and may thus be a promising strategy for sensitive evaluation of tumour target expression.

Fluorescence Reflectance Imaging of Macrophage-Rich Atherosclerotic Plaques Using an αvβ3 Integrin–Targeted Fluorochrome

“…Although numerous studies explained the potential of targeting a v b 3 to image myocardial angiogenesis (e.g., of the healing myocardium after infarction (19)), we hypothesized that a v b 3 may be a suitable target to visualize atherosclerotic plaques because it is highly expressed on macrophages (9) and binds MMP-2 (15), a key molecule for plaque destabilization. Fluorochrome labeling of RGD peptides (12,13,20) and tumor targeting with optical probes using planar reflectance and 3-dimensional tomographic imaging methods have been shown to be feasible (16,21). The RGD tripeptid sequence is an integrin-shared adhesive motif (22) with distinct different affinities to Arg-Gly-Asp-dependent integrins such as a v b 3 , a 5 b 1 , or a IIb b 3 and led to the concept that different integrins distinguish varieties in the conformation and sequential environment of various RGD sites (13,(23)(24)(25).…”

“…Briefly, a cyclic RGD peptide was labeled with Cy 5.5 dye by the stirring of both educts in the dark, followed by high-performance liquid chromotography purification. As reported previously, the identity of the labeled product was confirmed by high-resolution electrospray mass spectrometry (16). Before intravenous application, the integrity of the tracer was checked using photometry and fluorometry (U3310 UV/VIS spectrophotometer and F-4500 fluorescence spectrometer, respectively; Hitachi).…”

“…Labeling of Cyclo[Cys-Arg-Gly-Asp-Cys]-Gly-Lys Peptides were labeled as described elsewhere (16). Briefly, a cyclic RGD peptide was labeled with Cy 5.5 dye by the stirring of both educts in the dark, followed by high-performance liquid chromotography purification.…”

“…The mouse monocytic macrophagelike cell line RAW264.7 (TIB-71; American Type Culture Collection), human melanoma cells M21 (16), and human adenocarcinoma cell line MCF-7 (HTB-22; American Type Culture Collection) were cultured in RPMI 1640 (Invitrogen Corp.) supplemented with 10% fetal calf serum, penicillin, and streptomycin. M21 and MCF-7 cells were grown routinely in a monolayer culture at 37°C in a 5% CO 2 humidified air atmosphere.…”

Improved decision making for prioritizing tumor targeting antibodies in human xenografts: Utility of fluorescence imaging to verify tumor target expression, antibody binding and optimization of dosage and application schedule

“…[25][26][27][28][29] Over the past decades, such optical imaging modalities have undergone rapid development and been used to monitor primary tumor growth and metastases, 30,31 tumor cell and enzyme activity, [32][33][34] tumor cell surface receptors, [35][36][37] apoptosis, 38 anti-tumor treatment effects 39 and biodistribution and accumulation of fluorescencelabeled molecules, such as therapeutic antibodies. [40][41][42][43] The majority of this macroscopic in vivo research was not correlated with microscopic ex vivo fluorescence histology analysis.…”