Nano-hydrogel-based delivery system for dihydroartemisinin to enhance cuproptosis and synergize with anti-PD-1 therapy in triple-negative breast cancer.

As an aggressive subtype of breast cancer, triple-negative breast cancer (TNBC) displays limited therapeutic options and poor clinical prognosis. Thus, there is an urgent need for developing more effective treatment strategies to optimize the clinical management of TNBC. Dihydroartemisinin (DHA), one kind of artemisinin derivatives, exhibits promising antitumor activity mainly through inducing excessive generation of reactive oxygen species (ROS). However, some intrinsic disadvantages, including poor aqueous solubility, short circulation time, and low bioavailability, greatly limit its clinical application. In this research, we constructed an injectable pH/ROS-responsive composite hydrogel (Lip-DHA-CuS@Gel) co-loaded with liposomal DHA (Lip-DHA) and copper sulfide (CuS) nanoparticles to enhance the therapeutic efficacy against TNBC. The hydrogel system could serve as a localized drug depot, enabling sustained drug release and improved tumor retention. In the tumor microenvironment, Lip-DHA-CuS@Gel facilitated efficient intratumoral delivery of DHA and CuS, resulting in mitochondrial copper overload and increased ROS production, thereby synergistically inducing cuproptosis. Copper chelators tetrathiomolybdate (TTM) and D-penicillamine (DPA) could significantly reverse the antitumor effects of Lip-DHA-CuS@Gel in TNBC. In the 4T1 tumor-bearing BALB/c mice, Lip-DHA-CuS@Gel synergistically potentiated the antitumor immunity of PD-1 blockade by inducing the release of damage-associated molecular patterns (DAMPs) and promoting intra-tumoral infiltration of CD8⁺ T cells. Taken together, these findings suggested that Lip-DHA-CuS@Gel highlights significant therapeutic potential to induce cuproptosis and enhance immunotherapy responsiveness in TNBC.