Synthesis and evaluation of two NIR fluorescent cyclic RGD penta-peptides for targeting integrins

摘要: Interest in novel RGD peptides has been increasingly growing as the interactions between and integrins are basis for a variety of cellular functions medical applications such modulation cell adhesion, invasion, tumor angiogenesis, metastasis. In particular, we have interested NIR fluorescent potential optical contrast agents vivo imaging. Therefore, two cyclic penta-peptides conjugated with carbocyanine (Cypate), i.e. lactam-based cyclo[RGDfK(Cypate)] (1) disulfide-containing Cypate-cyclo(CRGDC)-NH 2 (2), were designed synthesized. The competitive binding assay purified α v β 3 integrin peptide ligands using 125 I-echistatin tracer showed that 1 had higher receptor affinity (IC 50 ~10 -7 M) than -6 M). Furthermore, internalization A549 cells vitro was less 2, revealed by fluorescence microscopy. These results suggest both lactam- disulfide-based should be further studied structurally functionally to elucidate advantages each class compounds.