Enhanced intracellular accumulation and cytotoxicity of bortezomib against liver cancer cells using N-stearyl lactobionamide surface modified solid lipid nanoparticles

Asialoglycoprotein receptors (ASGPRs) are highly expressed on hepatocytes and have been used for liver-targeted delivery and hepatocellular carcinoma (HCC) therapy. However, targeted delivery of bortezomib (BTZ) to HCC has not been reported. In this study, N-stearyl lactobionamide (N-SALB) with galactose (Gal) moiety was synthesized as a targeting agent and its structure was confirmed by FT-IR and NMR analyses. N-SALB surface-modified solid lipid nanoparticles (SLNs) loaded with BTZ (Gal-SLNs/BTZ) were developed to target BTZ delivery into HCC cancer cells. The Gal-SLNs/BTZ had an average particle size of 116.3 nm, polydispersity index (PDI) of 0.210, and zeta potential of -13.8 mV. TEM analysis showed their nanometer-sized spherical morphology. The encapsulation efficiency (EE) and drug loading (DL) capacity were 84.5 % and 1.16 %, respectively. Release studies showed that BTZ loaded inside the SLNs was slowly released over a period of 72 h at pH 7.4. Flow cytometry analysis showed significantly higher intracellular uptake of N-SALB-targeted nanoparticles than non-targeted nanoparticles in HepG2 cells. All lipid formulations showed good biocompatibility in the cytotoxicity study using MTT assay. Concentration-dependent cytotoxicity was observed for all formulations, with N-SALB-targeted nanoparticles demonstrating more cytotoxicity against HepG2 cells. The highest percentage of apoptosis was obtained for N-SALB-targeted nanoparticles compared to non-targeted nanoparticles (42.2 % and 8.70 %, respectively). Finally, biodistribution studies in HepG2 bearing nude mice showed that the accumulation of targeted nanoparticles in the tumor was significantly higher than non-targeted nanoparticles.