PT  - JOURNAL ARTICLE
AU  - Zitzmann, Sabine
AU  - Krämer, Susanne
AU  - Mier, Walter
AU  - Mahmut, Miriam
AU  - Fleig, Julian
AU  - Altmann, Annette
AU  - Eisenhut, Michael
AU  - Haberkorn, Uwe
TI  - Identification of a New Prostate-Specific Cyclic Peptide with the Bacterial FliTrx System
DP  - 2005 May 01
TA  - Journal of Nuclear Medicine
PG  - 782--785
VI  - 46
IP  - 5
4099  - http://jnm.snmjournals.org/content/46/5/782.short
4100  - http://jnm.snmjournals.org/content/46/5/782.full
SO  - J Nucl Med2005 May 01; 46
AB  - Peptides are useful tools for directing radioisotopes into tumors. We evaluated the ability of a bacterial peptide display system to isolate new prostate tumor-specific peptides. Methods: We used the bacterial FliTrx system to identify a new cyclic peptide that binds to prostate carcinoma. Serum stability and binding affinities of the 125I-labeled peptide were tested. Furthermore, the 131I-labeled peptide was used to evaluate its biodistribution. Results: Several peptides showing a potential consensus motif were identified. The new peptide MM-2 is stable in serum for up to 24 h. It binds to PC-3 cells, and this binding can be inhibited more than 70% with the unlabeled peptide. Binding to human umbilical vein endothelial cells (HUVECs) and PNT-2 cells is weaker, and competition (27%) in HUVECs is less efficient. The biodistribution showed moderate accumulation in tumor. Conclusion: Bacterial peptide display, an alternative to phage peptide display, can allow the identification of specific binding and stable peptides.