Multivalent Interactions: Synthesis and Evaluation of Melanotropin Multimers - Tools for Melanoma Targeting.

In order to develop agents for early detection and selective treatment of melanomas, high affinity and high specificity molecular tools are required. Enhanced specificity may be obtained by simultaneously binding to multiple cell surface targets via the use of multimeric analogs of naturally occurring ligands. Trimers targeting overexpressed melanocortin receptors have been found to be potential candidates for this purpose. In the present letter, we describe the synthesis and study of multimers based on a dendrimer-like scaffold. The binding affinity and activity results revealed that dendrimers promote multivalent interactions via statistical and/or cooperative effects on binding. Moreover, viability studies showed no significant toxicity at micromolar concentrations, which will allow these molecular complexes to be used in vivo. Finally, imaging studies showed effective internalization for all the molecules confirming their potential as delivery agents.