Integrin and matrix metalloprotease dual-targeting with an MMP substrate-RGD conjugate

Multimeric RGD-Based Strategies for Selective Drug Delivery to Tumor Tissues

RGD peptides have received a lot of attention over the two last decades, in particular to improve tumor therapy through the targeting of the αVβ3 integrin receptor. This review focuses on the molecular design of multimeric RGD compounds, as well as the design of suitable linkers for drug delivery. Many examples of RGD-drug conjugates have been developed, and we show the importance of RGD constructs to enhance binding affinity to tumor cells, as well as their drug uptake. Further, we also highlight the use of RGD peptides as theranostic systems, promising tools offering dual modality, such as tumor diagnosis and therapy. In conclusion, we address the challenging issues, as well as ongoing and future development, in comparison with large molecules, such as monoclonal antibodies.

Peptide-based delivery vectors with pre-defined geometrical locks

Design of peptide-based targeted delivery vectors with attributes of specificity and selective cellular targeting by fixing their topology and resulting electrostatic fingerprint is the objective of this study. We formulated our peptide design platform by utilizing the possibilities of side-chain induced geometric restrictions in a typical peptide molecule. Conceptually, we locked the conformation of the RGD/NGR motif of tumor homing peptides (THPs) by mutating glycine in these motifs with d-proline and tailed the peptides with a syndiotactic amphipathic segment for cellular penetration. The designed peptides were synthesized, characterized, and tested in vitro on various cell lines, including breast cancer (MDA-MB-231), cervical cancer (HeLa), osteosarcoma (U2-OS) and non-cancer mammary epithelial cells (MCF-10A), by flow cytometry and confocal microscopy. The results showed differential cellular uptake in different cell types, as a result of the distinct electrostatic fingerprint encoded in their design. The uptake of serum pre-treated peptides by cells reveals the retention of peptide activity even after the incubation with serum. In addition, peptide-methotrexate (MTX) conjugates compared to the methotrexate drug showed enhanced apoptotic cell death in MTX-resistant MDA-MB-231 cells, indicating the increase in MTX bioavailability.