Dual drug inhibitors loaded on a nanotheranostics and biomimetic platform for the synergistic treatment of pancreatic ductal adenocarcinoma

Rapid growth in bionanotechnologies towards the improvement of therapeutic strategies against cancer relies on the development of nanomedicine products, such as nanoparticles (NPs). NPs have enormous therapeutic potential for treating tumors, as they represent a way of preparing multi-functionality platforms, achieving sophisticated targeting strategies, enhancing drug delivery, attenuating drug toxicity on healthy organs, and protecting drugs from rapid clearance. Lately, the incorporation of multi-functional theranostic nanocarriers is allowing the simultaneous diagnosis and therapy of cancer, in conjunction with the co-delivery of drugs for combination therapies. However, challenges in the development of optimized NPs have to be addressed; their toxicological characterization, in terms of biocompatibility and immunogenicity, and their targeting selectivity are current limitations to overcome, to fulfill safety requirements and enhance site-specific delivery. This Master's Thesis work is inserted in a project funded by the European Community under Grant Marie Skłodowska-Curie Actions. Its focus relies on the development of a nanotheranostics and biomimetic platform loaded with dual drug inhibitors for the synergistic diagnosis and treatment of one of the most lethal and resistant types of cancer, pancreatic ductal adenocarcinoma. The developed nanoconstruct consists of a core of zinc oxide nanocrystals doped with the rare earth element gadolinium. The advantage of using this kind of nanocrystals relies on its low intrinsic toxicity and strong resistance to microbes, as well as its magnetic properties, enabling it to work as a contrast agent in magnetic resonance imaging (MRI) for diagnostic purposes. The functionalization of the nanocrystal surface with oleic acid and amino-propyl groups permits a fair stabilization in water-based media, the covalent labeling with fluorescent dyes, and the physical adsorption of two hydrophobic therapeutic agents, namely Sorafenib and Vismodegib. Finally, a lipid bilayer coating is provided on the nanocrystal-drug ensemble. This lipid bilayer not only enhances the biostability of the nanoconstruct but also allows the incorporation of a pancreatic cancer target peptide, CKAAKN, to address the tumor site. All these components of the nanoconstruct concur to the preparation of a multi-functional theranostic nanoplatform, able to address the tumor microenvironment by active targeting of some crucial signal pathways, with the consequent site-specific delivery of the above-mentioned drugs. The nanoplatforms obtained are characterized in terms of chemical structure and composition, morphology, dimension, and zeta potential. Their performance is tested in terms of cytotoxicity, cellular uptake, and apoptotic events, on two pancreatic cell lines (specifically BxPC-2 and a metastatic one, AsPC-1). The preliminary in vitro results indicate that the dual drug loaded nanoconstructs increased the treatment efficacy compared to their free drug counterparts, proving to be a feasible multimodal theranostic approach that deserves further research.