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BACKGROUND/AIM Extracellular vesicles (exosomes, EVs) (30-200 nm in diameter) are secreted by various cells in the body. Owing to the pharmaceutical advantages of EVs, an EV-based drug delivery system (DDS) for cancer therapy is expected to be the next-generation therapeutic system. However, preservation methods for functional and therapeutic EVs should be developed. Here, we developed the method of lyophilization of arginine-rich cell penetrating peptide (CPP)-modified EVs and investigated the effects of lyophilization on the characteristics of EVs. MATERIALS AND METHODS Particle size, structure, zeta-potential, and cellular uptake efficacy of the arginine-rich CPP-modified EVs were analyzed. The model protein saporin (SAP), having anti-cancer effects, was encapsulated inside the EVs to assess the cytosolic release of EV content after cellular uptake. RESULTS Lyophilization of the EVs did not affect their particle size, structure, zeta-potential, and cellular uptake efficacy; however, the biological activity of the encapsulated SAP was inhibited by lyophilization. CONCLUSION Lyophilization of EVs may affect SAP structures and/or reduce the cytosolic release efficacy of EV's content after cellular uptake and needs attention in EV-based DDSs.

Background/aim Gefitinib is a tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and has been approved for the treatment of non-small cell lung cancers (NSCLCs) with EGFR mutations. Here we demonstrated that gefitinib induced a significantly enhanced biological activity of succinate-tetrazolium reductase (STR) in mitochondria and mitochondrial membrane potential in HCC827 cells (EGFR mutation NSCLCs, sensitive to gefitinib) at a high cell density. Materials and methods We assessed the biological activity (STR, mitochondrial membrane potential, expression level of Bcl-2 family proteins) of gefitinib on NSCLCs at different cell densities. Results The 3D cell culture experiments showed the enhanced mitochondrial biological activity in clustered cell culture treated with gefitinib. Interestingly, the expression levels of Bcl-xL and Bax, were affected by the cellular number and gefitinib treatment. We also found that gefitinib prevented additive anticancer activity in the combinational treatment with doxorubicin, which induces mitochondria-dependent apoptotic cell death. Conclusion Our results indicate that gefitinib may work as a mitochondrial protector against combinational treatment with mitochondria-dependent anticancer agents in high-cell-density.

Gefitinib is a tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR) and has been approved for the treatment of non-small cell lung cancers (NSCLCs) with EGFR mutations. Here we demonstrated that gefitinib induced a significantly enhanced biological activity of succinate-tetrazolium reductase (STR) in mitochondria and mitochondrial membrane potential in HCC827 cells (EGFR mutation NSCLCs, sensitive to gefitinib) at a high cell density.We assessed the biological activity (STR, mitochondrial membrane potential, expression level of Bcl-2 family proteins) of gefitinib on NSCLCs at different cell densities.The 3D cell culture experiments showed the enhanced mitochondrial biological activity in clustered cell culture treated with gefitinib. Interestingly, the expression levels of Bcl-xOur results indicate that gefitinib may work as a mitochondrial protector against combinational treatment with mitochondria-dependent anticancer agents in high-cell-density.

Artemisinin is a compound isolated from the wormwood Artemisia annua L. It reacts with iron and forms cytotoxic free radicals. It is selectively more toxic to cancer than normal cells because cancer cells contain significantly more intracellular free iron. Previously, we found that covalently tagging artemisinin to transferrin enhanced the selectivity and toxicity of artemisinin toward cancer cells in vitro. In the present research, artemisinin-transferrin conjugate was tested in a rat breast cancer model.Breast tumors were induced in rats by subcutaneous implantation of rat MTLn3 breast cancer cells. Once tumors were formed, daily intravenous injections of artemisinin-transferrin conjugate were administered.The conjugate significantly retarded the growth rate of breast tumors in the rat. No significant side effect was observed in the rats during treatment.Artemisinin-transferrin conjugate could be developed into a potent therapeutic agent for cancer in humans.