Design and characterization of therapeutic nanocarriers inspired by exosomes secreted by colorectal cancer cells

Colorectal cancer (CRC) is one of the oncological malignancies with the highest incidence and mortality rates. The dominant cause for such a high death rate is at large associated to the development of metastatic diseases. Statistics indeed show that about 25% of CRC patients is already affected by metastasis in the moment of the primary tumor diagnosis and almost the 50% of the cases evolve towards the same direction. Several studies noticed that Extracellular Vesicles (EVs) secreted by CRC cells carry intercellular signals and promote the tumor cells colonization of distant organ-specific metastatic sites, like liver and lungs. In particular, tumor cells produce a much greater amount of vesicles than healthy cells, allowing significant cell-cell exchanges, since they carry with them incorporated proteins, DNA, mRNA and microRNAs. Cancer-derived EVs have also been observed to abundantly get internalized back in the cancer tissue that originated them. Thus, the research carried out in this Master Thesis aims at developing more precise and effective treatments of CRC. In particular it aims to design nanocarriers which have the same ability as the exosomes to target cells, that are able to fuse with the plasma membrane of the targets and deliver their content in the cytoplasm. In this way the nanocarriers inspired to those exosomes could be ideated as tumor-targeted drug delivery systems. The Thesis has focused on the design of lipidic formulations, inspired by exosomal membrane of HT29 human CRC cell line, which have been exploited in the preparation of liposomes and as vectors for amino-propyl functionalized iron-doped zinc oxide nanocrystals. Size and surface charge characterizations have been performed on the nanocarriers, to confirm the possibility of manipulating their surface properties and biological behaviour. Also the interaction of liposomes with the cell membrane was studied in vitro on HT-29 CRC cells and different processes of internalization were identified. Overall, this work proves how promising the combination of nanotechnologies and a bio-inspired approach is in the customization of anticancer nanocarriers and their optimization in terms of drug encapsulation and targeted release and ultimately to achieve a more efficient cancer treatment.