Bioinspired Exosome-Mimetic Nanovesicles for Targeted Delivery of Chemotherapeutics to Malignant Tumors

Abstract

Exosomes, the endogenous nanocarriers that can deliver biological information between cells, were recently introduced as new kind of drug delivery system. However, mammalian cells release relatively low quantities of exosomes, and purification of exosomes is difficult. Here, we developed bioinspired exosome-mimetic nanovesicles that deliver chemotherapeutics to the tumor tissue after systemic administration. The chemotherapeutics-loaded nanovesicles were produced by the breakdown of monocytes or macrophages using a serial extrusion through filters with diminishing pore sizes (10, 5, and 1 μm). These cell-derived nanovesicles have similar characteristics with the exosomes but have 100-fold higher production yield. Furthermore, the nanovesicles have natural targeting ability of cells by maintaining the topology of plasma membrane proteins. In vitro, chemotherapeutic drug-loaded nanovesicles induced TNF-α-stimulated endothelial cell death in a dose-dependent manner. In vivo, experiments in mice showed that the chemotherapeutic drug-loaded nanovesicles traffic to tumor tissue and reduce tumor growth without the adverse effects observed with equipotent free drug. Furthermore, compared with doxorubicin-loaded exosomes, doxorubicin-loaded nanovesicles showed similar in vivo antitumor activity. However, doxorubicin-loaded liposomes that did not carry targeting proteins were inefficient in reducing tumor growth. Importantly, removal of the plasma membrane proteins by trypsinization eliminated the therapeutic effects of the nanovesicles both in vitro and in vivo. Taken together, these studies suggest that the bioengineered nanovesicles can serve as novel exosome-mimetics to effectively deliver chemotherapeutics to treat malignant tumors.

Modularized Extracellular Vesicles: The Dawn of Prospective Personalized and Precision Medicine

“…Small lipophilic molecules, such as antioxidants, curcumin, and anticancer agents, can be passively loaded into EVs or EVMs by simple incubation 52, 93, 94. Drugs, including curcumin, show advanced stability and bioavailability when encapsulated compared to free‐state drugs and have been successfully used in preclinical research 95.…”

“…For instance, EVs or EVMs loaded with anticancer drugs were obtained after the parental cells were incubated with this drug 52, 98, 99. Furthermore, fluorescent lipophilic dyes are generally used as a tracer of EVs from conditioned medium after the parental cells have been labeled 100, 101…”

“…The primary technique to generate EVMs, crushing cells via serial extrusion through nanopore filter membranes with gradually reduced pore sizes (10, 5, and 1 µm) followed by isolation via two‐step density gradient ultracentrifugation, has been developed by Gho and co‐workers 52. In our unpublished work, we have added an extra extrusion step, using a 0.2 µm nanopore filter membrane immediately following the 1 µm nanopore filter membrane.…”

“…Recently, EV mimetic nanovesicles (EVMs), which have as much as a 120‐fold higher production yield compared to EVs from the same number of source cells, have been created by breaking down cells through serial extrusion 52. Furthermore, it has gradually been revealed that EVMs show similar properties to EVs;53, 54 therefore, the method of producing EVMs might be a much more effective way to manufacture modularized EVs.…”

Therapeutic biomaterials based on extracellular vesicles: classification of bio‐engineering and mimetic preparation routes

“…Those strategies rely on the principle of self-assembly of lipids and lipid membranes into spherical structures and the encapsulation of surrounding material into the aqueous cavity of generated nanovesicles. Current methods include extrusion over membrane filters [16,17,87], hydrophilic microchannels [88] or cell slicing by Si x N y blades [18] (see Table 4). …”