Self-delivery of a peptide-based prodrug for tumor-targeting therapy

A novel self-delivered prodrug system was fabricated for tumor-targeting therapy. In this nanosystem, the Arg-Gly-Asp-Ser (RGDS) tetrapeptide was used to improve the therapeutic index to integrin-overexpressing tumor cells. The antitumorous drug camptothecin was further appended to the epsilon-amino group of lysine by 20-O-succinyl linkage and controllably released via hydrolytic cleavage. Prodrug molecules self-assembled into fibrillar nano-architectures and achieved the capability of self-delivery after being injected subcutaneously into mice. Introduction of hydrophobic myristic acid favored the self-assembly and enhanced the cellular internalization of the prodrugs. In vitro and in vivo studies demonstrated that the self-assembled nanofibers could effectively target integrinoverexpressing tumorous cells and inhibit tumor growth via RGD-mediated specific targeting. Therefore, the traditional idea that fibrillar structures hold low therapeutic efficacy due to poor cell uptake can be challenged.