Development of a Novel Nanocarrier Focusing on the Physicochemical Properties of an Anti-cancer Therapy Drug<br/>—Development of Anti-cancer Nanoparticles Containing Vitamin E Derivative with Mulitifaceted Anti-cancer Effect—

Abstract

Successful cancer gene therapy is dependent upon the development of nanocarriers that exhibit anti-cancer effects via delivery of nucleic acids to the target site in tumor tissue. The effectiveness of such systems has typically relied on the potency of the anti-cancer nucleic acids, as conventional carriers do not exhibit inherent anti-cancer activity, serving only as vehicles for delivery. Ideal nanocarriers for effective cancer gene therapy should not only serve as delivery systems for transporting anti-cancer nucleic acids to the target tumor tissue, but should also exhibit their own inherent anti-cancer activity. α-tocopheryl succinate (TS) has attracted attention as a unique anti-cancer agent for its ability to induce apoptosis in various cancer cells; moreover, TS readily forms nanovesicles (TS-NVs). Thus, vesicles comprised of TS represent prospective tools for use as drug delivery systems (DDS) for cancer therapy. Owing to the low vesicle stability in the presence of divalent cations or serum, however, TS-NVs are not suitable for encapsulating nucleic acids, and require passive targeting delivery to tumor tissue via an enhanced permeability and retention effect. To improve the stability of TS-NVs, we developed novel nanovesicles comprised of TS and egg phosphatidylcholine (EPC), which can form a stable lamellar structure (TS-EPC-NVs). In this review, we introduce the development of nanovesicles comprised of TS as a novel DDS carrier and demonstrate the anti-cancer activity of both the encapsulated nucleic acids and the carrier itself.