Targeting tumors with cyclic RGD-conjugated lipid nanoparticles loaded with an IR780 NIR dye: In vitro and in vivo evaluation.

Like several 50nm-large nanocarriers, lipid nanoparticles (LNPs) can passively accumulate in tumors through the Enhanced Permeability and Retention (EPR) effect. In this study, we developed PEGylated LNPs loaded with IR780 iodide as a contrast agent for NIR fluorescence imaging and modified them with cyclic RGD peptides in order to target integrin avβ3. We demonstrate a specific targeting of the receptor with cRGD-LNPs but not with cRAD-LNP and standard LNP using HEK293(β3), HEK293(β3)-αvRFP, DU145 and PC3 cell lines. We also demonstrate that cRGD-LNPs bind to αvβ3, interfere with cell adhesion to vitronectin and co-internalize with αvβ3 within one hour. We then investigated their biodistribution and tumor targeting in mice bearing DU145 or M21 tumors. We observed no significant differences between cRGD-LNP and the non-targeted ones regarding their biodistribution and accumulation/retention in tumors. This suggested that despite an efficient formulation of the cRGD-LNPs, the cRGD-mediated targeting was not increasing the total amount of LNP that can already accumulate passively in the subcutaneous tumors via the EPR effect.