Multifunctional nanomedicine for the intracellular delivery of an antibody to CD44v6 expressing cancer cells

• Autor(a) principal: Vieira, Ana Isabel Baião
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/28411
• topic: Antibody fragment; Bevacizumab; CD44v6; Metastatic colorectal cancer; PLGA-PEG nanoparticles

Colorectal cancer (CRC) is one of the most incident and mortal cancers in the world, mainly due to its metastatic ability. CD44 receptor isoform containing exon 6 (CD44v6) in colorectal cells have been implied in many cancers associated process including metastasis. CD44v6 is a co-receptor for hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), along with c-Met and VEGF receptor 2 (VEGFR-2), respectively. Standard chemotherapy regimens recommend for metastatic stages of CRC are commonly associated with severe side effects because they act non-selectively. Therapies that act specifically against a molecular target enhance efficacy of the drugs, resulting in lower toxicity. One example is bevacizumab (Avastin®), an anti-angiogenic monoclonal antibody (mAb) that inhibits VEGF action. Drug delivery systems (DDS), as nanoparticles (NPs) can be conjugated with ligands in order to be directed to a specific molecular target. One type of ligand with high affinity to cell receptors are antibodies. In this work, it was developed an innovate nanosystem, with polymeric NPs of poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-PEG) loaded with bevacizumab and decorated with an antibody fragment (Fab) specific for CD44v6-expressing human cancer cells, the AbD15179 (v6 Fab). Bare and (-) Fab PLGA-PEG NPs were also developed to evaluate the specificity of v6 Fab. The NPs produced displayed sizes in the range of 200-300 nm and a negative surface electric charge between -5 and -10 mV, with an association efficiency (AE) of bevacizumab around 85%. Overall, the formulations at a concentration of 5 and 50 μg/mL did not show toxicity in cancer cells. The v6 Fab-PLGA-PEG NPs specifically bonded to the surface of cells overexpressing CD44v6 and this affinity was maintained with the encapsulation of bevacizumab. Also, PLGA-PEG NPs functionalized with v6 Fab were more internalized in cells than the bare and (-) Fab-PLGA-PEG NPs. To confirm the specificity of bevacizumab-loaded v6Fab-PLGA-PEG NPs, intracellular levels of bevacizumab and VEGF were evaluated after incubation of PLGA-PEG NPs. Intracellular levels of bevacizumab were significantly higher in cells incubated with v6 Fab-PLGA-PEG NPs. The percentage of intracellular VEGF levels did not show significance between the groups but was possible to observe a tendency in the decrease of VEGF levels after incubation with v6 Fab-PLGA-PEG NPs. In this work it was demonstrated that it is possible to encapsulate a mAb in PLGA-PEG NPs and then functionalize with a Fab for a specific and effective intracellular delivery of the drug. Though, their use in drug delivery requires further investigation and optimization.