A novel anti-VEGF165 monoclonal antibody-conjugated liposomal nanocarrier system: physical characterization and cellular uptake evaluation in vitro and in vivo

Abstract

Vascular endothelial growth factor (VEGF) is an important target for cancer therapy. In the present study, we conjugated the novel fully-human anti-VEGF165 monoclonal antibody, mAb165, with a PEGylated liposome (lip) to produce a monoclonal antibody-conjugated PEGylated liposome (mAb-lip). Physical characterization of mAb-lips showed an average particle size of 108nm. Using a bicinchoninic acid (BCA) assay, the coupling efficiency of mAb165 conjugated to the liposome was 69.8±0.5μg mAb/μmol phospholipid. In addition, we confirmed that conjugation between mAb165 and the liposome did not affect the structure and VEGF binding affinity of the antibody. Cell uptake of mAb-lips was assessed in four cell lines: MCF-7, HepG-2, SGC-7901, and L02 cells. Confocal microscopy and flow cytometry demonstrated that there was no significant difference in cell uptake between mAb-lips and mAb-free liposome either in VEGF-expressing tumor cells or normal cells. Moreover, the cytotoxicity of paclitaxel encapsulated in mAb-lips was not increased in the four cell lines. However, in BALB/c nude mice bearing MCF-7 xenografts, mAb-lips showed superior targeting activity to tumor tissues when compared with the unmodified liposome, which was demonstrated by the fact that rhodamine-labeled mAb-lips exhibited higher fluorescence intensity in tumor tissues than the unmodified liposome. Thus, our study indicated that mAb-lips may have the potential to enhance the therapeutic index of anticancer agents through targeted delivery to tumor cells in vivo.

Keywords: Cellular uptake; Cytotoxicity; PEGylated liposomes; Targeted delivery; VEGF mAb.