CCK8 peptide-labeled Pluronic® F127 micelles as a targeted vehicle of gold-based anticancer chemotherapeutics

The bioavailability and target selectivity of chemotherapeutics are significant issues in drug development. Here, we report the loading of the antiproliferative gold(III) complex, dibromo[ethyl-N-(dithiocarboxy-kS,kS′)-N-methylglycinato] gold(III) (AuL12), into the lipophilic core of micelles produced from the surfactant Pluronic® F127 (PF127). When AuL12 is encapsulated in PF127-based micelles it remains stable in saline solution up to 72 h with the gold center in the +3 oxidation state. PF127-based aggregates are efficient carriers as they enhance the water solubility of the gold complex. In vitro studies indicate that after micelle encapsulation, AuL12 gold complex preserves its antiproliferative efficacy. Moreover, by labeling the hydrophilic shell of micelles with the bioactive CCK8 peptide, the aggregates act as target-selective vehicles. In fact, cytotoxic activity towards the A431 cells overexpressing the CCK2 receptors is 10-fold higher than that towards the control cells.