Specific PET Imaging Probes for Early Detection of Prostate Cancer Metastases
Annual rept. 1 May 2008-30 Apr 2009
TEXAS UNIV AT AUSTIN
Pagination or Media Count:
Polyarginines are a group of small peptides that have been used as drug delivery vehicles due to their capability of penetrating cell membranes. In one of our studies using such a peptide to deliver a therapeutic moiety to various prostate cancer cell lines, we surprisingly discovered that the peptide had remarkably high preference to prostate tissues. This specificity, which has not been reported before, prompted us to exploit this group of peptides for the early detection of prostate tumor metastases. Promisingly, in our preliminary studies, the peptide labeled with 64Cu can clearly reveal metastases in a tumor-bearing animal model. In the first year of this project, we have shown that glycosaminoglycans play an important role in the uptake of the peptide in four prostate cancer cell lines. Among the inhibitors tested, dextran sulfate, protamin sulfate and pentosan sulfate are highly potent. Our biodistribution studies indicated that the preference uptake was specific to the peptide length of polyarginines. Further we have accomplished the synthesis of the proposed multifunctional chelators and the construction of their multivalent peptide conjugates. The peptide constructs were efficiently labeled with 64Cu under mild conditions with 30-min. Preliminary in vitro binding assay demonstrated the desired multivalent effect rendered by the designed scaffold, and the radiolabeled conjugates showed high in vitro and in vivo stability.
- Medicine and Medical Research