| dc.description | Early and reliable diagnosis of melanoma, a skin tumor
with a poor prognosis, is extremely important. Phage
display peptide libraries are a convenient screening
resource for identifying bioactive peptides that interact with
cancer targets. The aim of this study was to evaluate two
technetium-99m tracers for angiogenesis detection in a
melanoma model, using cyclic pegylated pentapeptide with
RGD and NGR motifs conjugated with the bifunctional
chelator mercaptoacetyltriglycine (MAG3). The conjugated
peptides (10 ll of a lg/ll solution) were labeled with
technetium-99m using a sodium tartrate buffer.
Radiochemical evaluation was carried out by instant
thin-layer chromatography and confirmed by
high-performance liquid chromatography. The partition
coefficient was determined and internalization assays were
performed in two melanoma cell lines (B16F10 and
SKMEL28). Biodistribution evaluation of the tracers was
carried out in healthy animals at different time points and
also in tumor-bearing mice, 120 min post injection.
Blocking studies were also conducted by coinjection of
cold peptides. The conjugates displayed a rather similar
pharmacokinetic profile. They were radiolabeled with high
radiochemical purity (> 97%) and both were hydrophilic
with preferential renal excretion. Yet, tumor uptake
was higher for human than for murine melanoma
cells, especially for [99mTc]-MAG3-PEG8-c(RGDyk)
(7.85?? 2.34%injected dose/g 120 min post injection).
The performance of [99mTc]-MAG3-PEG8-c(RGDyk)
was better than the NGR tracer with regard to
human melanoma uptake. In this sense, it should be
considered for future radiotracer studies of tumor
diagnosis. Melanoma Res 22:45???53 c 2012 Wolters
Kluwer Health | Lippincott Williams & Wilkins. | |
