Aloperine exerts anti-tumor effect and activates the tumor cell-intrinsic STING pathway in gallbladder cancer

Background Aloperine (ALO), a quinolizidine-type alkaloid isolated from a natural Chinese herb, exhibits anticancer activity in several malignancies, but its efficacy and mechanisms in gallbladder cancer (GBC) remain undefined. Methods Human GBC cell lines (GBCs) were treated with ALO and assessed for viability, colony formation, 5-Ethynyl-2′-deoxyuridine (EdU) incorporation and apoptosis. Autophagic flux and related signaling were evaluated by western blotting and immunofluorescence. In vivo antitumor activity was determined in a nude mouse xenograft model. Results ALO markedly inhibited the proliferation ability of GBCs and disrupted autophagosome–lysosome fusion, leading to reactive oxygen species (ROS) accumulation and apoptosis. Furthermore, ALO induced DNA damage and nuclear release of double-stranded DNA (dsDNA) to cytoplasm, leading to cyclic-GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING)-mediated interferon (IFN) pathway activation and enhancing natural killer cells (NK cells) activation in vitro. In vivo, ALO reduced subcutaneous GBCs xenograft volume and weight and, along with increased cleaved caspase-3 and BAX expression in tumor tissues, confirming tumor cell apoptosis. Conclusions These findings indicate that ALO may serve as a novel therapeutic candidate for gallbladder cancer by inhibiting autophagic flux to induce ROS-mediated apoptosis while activating the cGAS–STING–IFN pathway to enhance antitumor immunity.