In Vitro and in Vivo Enhancement of Antitumoral Activity of Liposomal Antisense Oligonucleotides by Cineole as a Chemical Penetration Enhancer

Abstract

Cellular uptake and cytoplasmic release of liposomal antisense oligonucleotides (AsODNs), which can act as rate-limiting steps, are still remained to be completely optimized. Here, the possibility of enhancing such processes at cellular and animal levels by cineole, as a penetration enhancer, was investigated. A cationic nanoliposome containing an AsODN against PKC-α and a cineole-containing nanoliposome were prepared and characterized. The effect of nanoliposomal cineole on sequence-specific cytotoxicity of nanoliposomal AsODN against A549, was studied in vitro (MTT, flow cytometry, fluorescence microscopy, and real time PCR) and in vivo (xenograft lung tumor in nude mice) using different concentrations and treatment times. Results showed specific cytotoxicity of nanoliposomal AsODN was increased significantly from 11% to 25% when A549 cells were exposed to 10 μg/mL cineole for 1 or 4 hours. This inhibitory effect was further increased to about 40% when the concentration was increased to 40 μg/mL for 1 hour. In animal studies, cineole significantly decreased the tumor volume (about 75%) and increased its doubling time from 13 days to 31 days. A linear relationship exists between cineole concentration and its enhancement effects. Finally it was concluded that cineole, and possibly other membrane fluidizers, can improve nanoliposomal gene therapy at cellular and animal levels.