Immunotherapy is revolutionizing the way we treat cancers in patients. By using combinations of immunotherapeutics we can overcome the drug resistance, for example, by the administration of a cancer vaccine or an oncolytic virus followed by addition of an immune checkpoint inhibitors. Here, we tested a new concept and evaluated the innovation of the biohybrid and biodegradable nanovaccines by combining different parts of a nanovaccine. This was based on a biohybrid cell membrane based technology, which contain the cancer cells’ antigenic sources.
Here, we developed a biohybrid multistage nanovaccine formulation and evaluated its anticancer efficacy in murine tumor models. In order to do so, we first assessed the parameters affecting the formulation of the biohybrid nanosystems, and further elucidated the influence of the cell membrane coating on the colloidal stability of the nanoparticles in physiological conditions, as well as their biocompatibility when using different cancer cell membrane types. Next, we demonstrated the effect of the cell membrane-wrapping on the cellular uptake in the presence of inhibitors of selective uptake pathways, and evaluated the differences between naked and coated nanoparticles.
Then, we engineered a multistage nanovaccine made of inorganic nanoparticles (nanoporous silicon) enveloped in acetalated dextran biopolymer using the glass capillary microfluidics technology, followed by the cloaking with cancer cell membranes. We further evaluated in very detail the immunological profile of the nanovaccines, first in vitro, by assessing the expression of co-stimulatory signals and the secretion of proinflammatory cytokines. In the next step, we also assessed in vitro the efficacy of the biohybrid nanovaccine as a monotherapy and in combination with an immune checkpoint inhibitor in both less aggressive and aggressive melanoma murine models.
Finally, at the last stage of the project, we exchanged the adjuvant core of the nanovaccince from the combination of inorganic nanoparticles+biopolymer (synthetic nanoparticles) to an oncolytic adenoviruses and investigated: (i) the translatability of the technique; (ii) the influence of the cell membrane-coating on the viral infectivity; and (iii) the preventive and therapeutic efficacy of the vaccine in different tumor models (melanoma and lung). The viral encapsulation changed the uptake mechanisms of the virus, enabling enhanced infectivity also in virus-resistant cell lines in vitro and in vivo. Moreover, the cell membrane layer effectively shielded the virus from neutralizing antibodies. Based on these results, we further investigated the efficacy of the viral nanovaccine in melanoma and lung adenocarcinoma. In a highly immunogenic melanoma model (B16.OVA) and in a solid lung adenocarcinoma model (LL/2) the intratumoral administration of the developed nanovaccine controlled the tumor growth in all the animals, while in B16.F10 the tumors were controlled in 66% of the animals. The vaccination with our developed nanovaccine elicited a local and systemic tumor-specific cell-mediated immune response, as determined by the analysis of the immune contexture in the tumor microenvironment and in the spleen. Moreover, the pre-immunization with the nanovaccine wrapped in
tumor-matched membranes controlled the tumor growth and prolonged the overall survival of tumor challenged mice.
Overall, the nanovaccines engineered with nanoporous silicon nanoparticles and oncolytic adenovirus-based biohybrid nanovaccines were developed, providing new insights on the structure and efficacy of these systems as therapeutic cancer nanovaccines. The nanovaccine resulted in greater therapeutic effect for cancer immunotherapy when compared with the traditional cancer therapies. The exploitation of biological elements (cell membranes and viruses) as
nanosized systems takes advantage of evolution to address some of the current issues related to nanoparticles in cancer therapy. These systems can provide additional features that have not been completely recreated on a lab bench, allowing also for an increased understanding of the properties needed to improve synthetic particles. The application of our technology may allow to bring a personalized patient cancer therapy/treatment into the clinics. More importantly, the applicability of biohybrid and biodegradable nanovaccines may extend beyond the cancer treatment, such as cardiovascular and autoimmune diseases.
