Tumor-homing, pH- and ultrasound-responsive polypeptide-doxorubicin nanoconjugates overcome doxorubicin resistance in cancer therapy.

Nanomedicines hold promise in overcoming drug resistance in cancer therapy, but the in vivo therapeutic efficacy is limited by their inefficient tumor targeting, poor tumor penetration, low cellular uptake and insufficient drug release. Here we report tumor-homing, pH- and ultrasound-responsive polypeptide-doxorubicin nanoconjugates for overcoming doxorubicin resistance. These nanoconjugates show accelerated cellular uptake and doxorubicin release and thus enhanced cytotoxicity to doxorubicin-resistant cancer cells when exposed to ultrasound. In a doxorubicin-resistant breast cancer mouse model, they exhibited improved tumor accumulation and penetration following exposure to ultrasound. More importantly, they displayed significantly improved in vivo anticancer efficacy without appreciable side effects post ultrasound irradiation. These findings suggest that these nanoconjugates are promising as a new class of intelligent nanomedicines for overcoming drug resistance in cancer therapy.