Photodynamic therapy (PDT) is a promising and clinically approved method for the treatment of cancer. However, the efficacy of PDT is often limited by the poor selectivity and distribution of the... Show morePhotodynamic therapy (PDT) is a promising and clinically approved method for the treatment of cancer. However, the efficacy of PDT is often limited by the poor selectivity and distribution of the photosensitizers (PS) toward the malignant tumors, resulting in prolonged periods of skin photosensitivity. In this work, we present a simple and straightforward strategy to increase the tumor distribution, selectivity, and efficacy of lipophilic PS zinc phthalocyanine (ZnPc) in colon cancer by their stabilization in purified, naturally secreted extracellular vesicles (EVs). The PS ZnPc was incorporated in EVs (EV-ZnPc) by a direct incubation strategy that did not affect size distribution or surface charge. By using co-culture models simulating a tumor microenvironment, we determined the preferential uptake of EV-ZnPc toward colon cancer cells when compared with macrophages and dendritic cells. We observed that PDT promoted total tumor cell death in normal and immune cells, but showed selectivity against cancer cells in co-culture models. In vivo assays showed that after a single intravenous or intratumoral injection, EV-ZnPc were able to target the tumor cells and strongly reduce tumor growth over 15 days. These data expose opportunities to enhance the potential and efficacy of PDT using simple non-synthetic strategies that might facilitate translation into clinical practice. Show less
Extracellular vesicles (EVs) are important mediators of intercellular communication that participate in many physiological/pathological processes. As such, EVs have unique properties related to... Show moreExtracellular vesicles (EVs) are important mediators of intercellular communication that participate in many physiological/pathological processes. As such, EVs have unique properties related to their origin, which can be exploited for drug delivery applications in cell regeneration, immunosuppression, inflammation, cancer treatment or cardioprotection. Moreover, their cell-like membrane organization facilitates uptake and accumulation in specific tissues and organs, which can be exploited to improve selectivity of cargo delivery. The combination of these properties with the inclusion of drugs or imaging agents can significantly improve therapeutic efficacy and selectivity, reduce the undesirable side effects of drugs or permit earlier diagnosis of diseases. In this review, we will describe the natural properties of EVs isolated from different cell sources and discuss strategies that can be applied to increase the efficacy of targeting drugs or other contents to specific locations. The potential risks associated with the use of EVs will also be addressed. Show less
Active co-delivery of tumor antigens (Ag) and alpha-galactosylceramide (alpha-GalCer), a potent agonist for invariant Natural Killer T (iNKT) cells, to cross-priming CD8 alpha(+) dendritic cells ... Show moreActive co-delivery of tumor antigens (Ag) and alpha-galactosylceramide (alpha-GalCer), a potent agonist for invariant Natural Killer T (iNKT) cells, to cross-priming CD8 alpha(+) dendritic cells (DCs) was previously shown to promote strong anti-tumor responses in mice. Here, we designed a nanoparticle-based vaccine able to target human CD141(+) (BDCA3(+)) DCs - the equivalent of murine CD8 alpha(+) DCs - and deliver both tumor Ag (Melan A) and alpha-GalCer. This nanovaccine was inoculated into humanized mice that mimic the human immune system (HIS) and possess functionaliNKT cells and CD8(+) T cells, called HIS-CD8/NKT mice. We found that multiple immunizations of HIS-CD8/NKT mice with the nanovaccine resulted in the activation and/or expansion of human CD141(+) DCs andiNKT cells and ultimately elicited a potent Melan-A-specific CD8(+) T cell response, as determined by tetramer staining and ELISpot assay. Single-cell proteomics further detailed the highly polyfunctional CD8(+) T cells induced by the nanovaccine and revealed their predictive potential for vaccine potency. This finding demonstrates for the first time the unique ability of humaniNKT cells to license cross-priming DCsin vivoand adds a new dimension to the current strategy of cancer vaccine development. Show less
