Effective intracellular delivery of bevacizumab via PEGylated polymeric nanoparticles targeting CD44v6 receptor in colon cancer cells
Colorectal cancer (CRC) is one of the most incident and mortal cancers in the world, mainly due to its metastatic and metabolic ability. CD44 receptor isoform containing exon 6 (CD44v6) is a transmembrane protein that plays an important role in the establishment of tumors and metastasis, which made this molecule a potential target for therapy and/or diagnosis of tumors. Aiming at a targeted therapy, the anti-VEGF monoclonal antibody (mAb), bevacizumab was loaded into poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-PEG) nanoparticles (NPs) functionalized with an antibody fragment (Fab) specific for CD44v6-expressing human cancer cells. NPs sized in the range of 150-250 nm and were negatively charged between -5 and -10 mV, with an association efficiency (AE) of bevacizumab of 86%. The v6 Fab-PLGA-PEG NPs containing bevacizumab specifically bonded to CD44v6 cell surface receptor and exhibited higher internalization into CD44v6+ epithelial cells compared to the bare and (-) Fab-PLGA-PEG NPs. To understand the biological effect of NP targeting, intracellular levels of bevacizumab and VEGF were evaluated after incubation of targeted and untargeted NPs. Intracellular levels of bevacizumab were significantly higher in cells incubated with v6 Fab-PLGA-PEG NPs and these NPs also allowed a significant decrease in the intracellular VEGF compared to the untargeted NPs and free bevacizumab. PLGA-PEG NPs, surface-functionalized with a v6-specific Fab have the potential to intracellularly deliver bevacizumab in CD44v6 expressing cancer cells.