Nanoparticles carrying paclitaxel and anti-miR-221 for breast cancer therapy triggered by ultrasound.

Nanomaterials have been well demonstrated to have the potential to be used for tumor cell-targeted drug delivery. Targeted inhibition of miR-221 was proved to promote the sensitivity of triple genitive breast cancer (TNBC) cells to chemo-drugs. In order to improve the chemotherapeutic effect in TNBC, herein, we developed a novel kind of nanoparticles shelled with PLGA and loaded with perfluoropentane (PFP), paclitaxel (PTX), and anti-miR-221 inhibitor, which was named PANP. Ultrasound-triggered vaporization of PFP in PANPs was utilized for real-time imaging track of the nanoparticles in vivo. In addition, macrophages were applied for the internalization of PANPs to form RAW-PANP with strong chemotaxis to accumulate around cancer cells. Nanoparticles with different contents did not cause M2 polarization compared with the control group but caused polarization toward M1. We compared the inherent tumor-homing behavior of macrophages containing different contents with that of normal macrophages and no significant abnormalities were observed. After injection into the tumor-burden mice, RAW-PANPs showed enrichment within tumor tissues. Upon the ultrasound cavitation-triggered burst, PTX was released in the tumor. Meanwhile, the release of anti-miR-221 improved the sensitivity of tumor cells to PTX. As a result, RAW-PANPs showed high efficiency in suppressing TNBC cell proliferation in vitro and inhibiting tumor growth and progression in vivo. The treatments did not induce liver, heart, or kidney injury. In conclusion, the current study not only developed a macrophage-carried, ultrasound-triggered, cancer cell-targeted chemotherapeutic system, but also demonstrated a miRNA-based technique to promote drug sensitivity of cancer cells, which holds strong potential to treat patients with TNBC, especially for those suffering drug-resistance. The innovation of this study is to use macrophages to deliver nanoparticles to the tumors and then use ultrasound locally to burst the nanoparticles to release the miRNA and PTX.