Small molecule-drug conjugates (SMDCs) mimicking the RGD sequence (-Arg-Gly-Asp-) with a non-peptide moiety require a pharmacophore-independent attachment site. A library of 36 sulfonamide-modified RGD mimetics with nM to pM affinity for integrin αV β3 was synthesized and analysed via DAD mapping. The best structure of the conjugable RGD mimetic was used and a linker was attached to an aromatic ring by Negishi cross-coupling. The product retained high affinity and selectivity for integrin αV β3 . The conjugable RGD mimetic was then attached to an enzymatically cleavable GKGEVA linker equipped with a self-immolative PABC and the antimitotic drug monomethyl auristatin E (MMAE). The resulting SMDC preferred binding to integrin αV β3 over α5 β1 in a ratio of 1 : 4519 (ELISA) and showed selectivity for αV β3 -positive WM115 cells over αV β3 -negative M21-L cells in the in vitro cell adhesion assay as well as in cell viability assays with a targeting index of 134 (M21-L/WM115).
Keywords: RGD peptide; antitumour agents; cytotoxicity; drug delivery; peptidomimetics.
© 2022 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.