Dual-responsive nanoscale ultrasound contrast agent as an oxidative stress amplifier for enhanced DNA damage in BRCA-proficient ovarian cancer

PARP inhibitor (PARPi)-based synthetic lethal therapies have displayed limited benefits in BRCA-proficient ovarian cancer. To potentiate the application of PARPi, an ultrasound contrast agent OLA-NDs for delivery of the PARPi olaparib (OLA) was established for enhancing DNA damage by blocking DNA repair. OLA-NDs were endowed with endogenous pH- and exogenous ultrasound (US)-responsiveness to target tumors, as well as contrast-enhanced US imaging for diagnostic and therapeutic integration. OLA-NDs could upregulate NOX4 to induce oxidative stress and sensitize BRCA wild-type A2780 cells to DNA oxidative damage through the utilization of ultrasound-targeted microbubble destruction (UTMD). In addition, the strategy further increased ROS production by interfering with mitochondrial function, thereby exacerbating DNA double-strand breaks (DSBs) and inducing mitochondria-mediated apoptosis. As a consequence, the combined application of UTMD and OLA-NDs demonstrated significant antitumor effects in vitro and in vivo . This combined strategy of amplifying oxidative damage improved lethality by promoting DNA DSBs and apoptosis with reduced adverse side effects, which would provide new insight for the clinical application of PARPi in BRCA-proficient ovarian cancer.