Preferentially released miR-122 from cyclodextrin-based star copolymer nanoparticle enhances hepatoma chemotherapy by apoptosis induction and cytotoxics efflux inhibition

Chemotherapy, as one of the most commonly used treatment modalities for cancer therapy, provides limited benefits to hepatoma patients, owing to its inefficient delivery as well as the intrinsic chemo-resistance of hepatoma. Bioinformatic analysis identified the therapeutic role of a liver-specific microRNA — miR-122 for enhancing chemo-therapeutic efficacy in hepatoma. Herein, a cyclodextrin-cored star copolymer nanoparticle system (sCDP/DOX/miR-122) is constructed to co-deliver miR-122 with doxorubicin (DOX) for hepatoma therapy. In this nanosystem, miR-122 is condensed by the outer cationic poly (2-(dimethylamino) ethyl methacrylate) chains of sCDP while DOX is accommodated in the inner hydrophobic cyclodextrin cavities, endowing a sequential release manner of miR-122 and DOX. The preferentially released miR-122 not only directly induces cell apoptosis by down regulation of Bcl-w and enhanced p53 activity, but also increases DOX accumulation through inhibiting cytotoxic efflux transporter expression, which realizes synergistic performance on cell inhibition. Moreover, sCDP/DOX/miR-122 displays remarkably increased anti-tumor efficacy in vivo compared to free DOX and sCDP/DOX alone, indicating its great promising in hepatoma therapy.