Antioxidant micelles for bortezomib delivery

Reactive oxygen species (ROS) serve important regulatory roles in cellular processes. However, elevated ROS levels have been linked with several diseases such as cancer. ROS has been known to stimulate cancer cell proliferation and enhance angiogenesis, a process crucial for tumor development and metastasis. Previously, we reported on catechol-bearing micelles capable of scavenging ROS and blocking angiogenesis. Here, we investigate whether the micelles could be loaded with a chemotherapeutic while maintaining its ROS-scavenging activity. Since bortezomib (BTZ), a boronic acid-containing drug, can interact with catechol groups in a pH-dependent manner, we investigated its loading into the micelles. The BTZ-loaded micelles were prepared by mixing of the catechol-bearing micelles and BTZ in phosphate buffer at pH 7.4. We used dynamic light scattering, atomic force microscopy, and surface tension measurements to investigate the effect of BTZ on micelle size and structural stability. The BTZ-loaded micelles maintained their ROS-scavenging activity and released BTZ in a pH-dependent manner. Furthermore, the BTZ-loaded micelles showed cytotoxicity in MCF7 human breast cancer cells. The micelles may show promise as a platform in cancer treatment by delivering the chemotherapeutic BTZ and blocking angiogenesis at the same time.