Multi-targeted stimuli-sensitive mixed micelles as a strategy for cancer therapy

Abstract

Conventional drugs have for long been investigated as potential therapeutic agents for the treatment of cancer, one of the leading causes of death worldwide. Recently, combination of these drugs with small non-coding RNAs has become a promising strategy to overcome the development of drug resistance. Additionally, the use of stimuli-sensitive drug delivery systems has emerged as a strategy to improve targeting of diseased tissues and reduce the damage to non-targeted organs.The general aim of this study was to develop, characterize and test a pharmaceutical preparation whose action is triggered by the enzymatic activity and redox conditions typical of tumor microenvironments. We hypothesized that overexpression of matrix metalloproteinase 2 (MMP2) and glutathione (GSH) in the tumor would guarantee a targeted delivery of Doxorubicin (Dox) and miRNA-34a, increasing bioavailability of both therapeutic agents and reducing off-target effects.A Dox prodrug and lipid-modified miRNA-34a were successfully synthesized and incorporated into mixed micelles (MM). The stimuli-sensitivity of both components was demonstrated in monolayer and spheroid models of cell culture in vitro. The level of MMP2 expression was a key factor to determine the localization of the Dox prodrug in the cytoplasm or cell nuclei. The cytotoxic effect in a monolayer model of soft tissue sarcoma was as high as 80%. The prodrug was also effective against breast adenocarcinoma and glioblastoma. The treatment with MMP2-sensitive MM significantly reduced cell motility and migration when compared to group control.iii GSH-sensitive MM lowered mRNA levels of survivin (» 55%), Bcl2 (» 65%) and notch1 (» 45%) in soft tissue sarcoma cells. Combination therapy with Dox prodrug and miRNA-34a inhibited over 90% of Bcl2 production. Dual stimuli-sensitive MM killed 2.4 to 3.6 times more cells compared to the single treatments by arresting the cells in S phase of their cell cycle.In vivo trials in tumor-bearing mice significantly inhibited growth of soft tissue sarcoma and glioblastoma xenografts and avoided weight loss caused by free Dox.