Dottorato in BIOLOGIA CELLULARE E DELLO SVILUPPO

Titolo della tesi: Drug resistance in metastatic melanoma: Development of nanoparticles for therapeutic microRNA tumour delivery

One of the most important challenges facing the oncologists today is focused on studying and preventing the escape of cancer cells from the action of chemotherapeutic agents. Emerging data support the rationale of combined therapies in advanced melanoma. The association of drugs with different mechanisms of action can reduce the frequency of resistant clone selection. For this purpose, we screened a library of drugs and selected PIK-75, an inhibitor PI3K/AKT pathway, which combined with vemurafenib or dabrafenib, inhibitors of MAPK/ERK pathway, showed a strong synergistic role. This action is enhanced by the presence of microRNA126 (miR126). Thus, one of the aims of this project was to develop a system able to deliver miR126 to melanoma cells in a combined therapy with above indicated PI3K/AKT and/or MAPK/ERK inhibitors. We synthetized and characterized chitosan nanoparticles containing miR126 (CS-126s) and we functionalized them by conjugation with a single chain antibody against CSPG4, a specific melanoma marker (Ab-CS126s). Subsequently, as a delivery system, we used miR126- enriched exosomes (EXO-miR126s) as vectors. CS-126s and Ab-CS-126s have been characterized and tested in in vitro experiments, demonstrating their ability to miR126 delivering. Moreover, experiments carried out on a mouse metastatic model also allowed us to obtain preliminary results on the real ability of Ab-CS-126s to inhibit the metastasis process of late-stage melanoma.