Riboflavin (RF) is an essential vitamin for cellular metabolism. Recent studies have shown that RF is internalized through RF transporters, which are highly overexpressed by prostate and breast cancer cells, as well as by angiogenic endothelium. Here, we present an optimized synthesis protocol for preparing tailor-made amphiphilic phospholipid-based RF derivatives using phosphoramidite chemistry. The prepared RF amphiphile - RfdiC14 - can be inserted into liposome formulations for targeted drug delivery. The obtained liposomes had a hydrodynamic size of 115±5 nm with narrow size distribution (PDI 0.06) and a zeta potential of -52±3 mV. In vitro uptake studies showed that RfdiC14-containing liposomes were strongly internalized in HUVEC, PC3 and A431 cells, in a specific and transporter-mediated manner. To assess the RF targeting potential in vivo, an amphiphile containing PEG spacer between RF and a lipid was prepared - DSPE-PEG-RF. The latter was successfully incorporated into long-circulating near-infrared-labelled liposomes (141±1 nm in diameter, PDI 0.07, zeta potential of -33±1 mV). The longitudinal µCT/FMT biodistribution studies in PC3 xenograft bearing mice demonstrated similar pharmacokinetics profile of DSPE-PEG-RF-functionalized liposomes compared to control. The subsequent histological evaluation of resected tumors revealed higher degree of tumor retention as well as co-localization of targeted liposomes with endothelial cells emphasising the targeting potential of RF amphiphiles and their utility for the lipid-containing drug delivery systems.
Bioconjugate chemistry. 2016 Jul 14 [Epub ahead of print]
Nataliia Beztsinna, Yoanna Tsvetkova, Matthias Bartneck, Twan Lammers, Fabian Kiessling, Isabelle Berque-Bestel