Objective Reactive oxygen species (ROS)-responsive co-loaded elemene (Ee) and chlorin e6 (Ce6) liposomes (Ee-Ce6-L) were prepared, characterization of their physicochemical properties, and evaluated for their inhibitory effects on bladder cancer 5637 cells. Methods The synergistic ratio of elemene and Ce6 (Ee + Ce6) was screened using the MTT assay. Ee-Ce6-L was prepared via the thin-film hydration method and characterized for morphology, particle size, encapsulation efficiency, drug loading capacity, stability, ROS generation capacity, and in vitro release rate. MTT assays evaluated the cytotoxicity of Ee-Ce6-L against 5637 cells. Annexin V-FITC/PI double staining was used to study the apoptotic effects of Ee-Ce6-L on cells. Fluorescence microscopy and a fluorometer were employed to examine its impact on ROS generation capacity and mitochondrial membrane potential (MMP). Western blotting analysis was conducted to investigate the expression of apoptosis pathway-related proteins. Results Ee + Ce6 exhibited synergistic effects across the 40:1 to 200:1 concentration range, with optimal synergy observed at 120:1; Ee-Ce6-L exhibited good stability and dispersibility. After irradiation with 660 nm laser, the particle size changed from (194.27 ± 0.20) nm to (390.97 ± 2.76) nm, and the ζ potential shifted from (−19.06 ± 0.07) mV to (−6.30 ± 0.34) mV. In vitro release experiments demonstrated that Ee-Ce6-L exhibits dual functions of sustained release and light-controlled drug release; the encapsulation efficiencies of elemene and Ce6 were (94.02 ± 0.38)% and (96.95 ± 0.70)%, respectively, while the drug loading capacities of Ee and Ce6 were (11.51 ± 0.46)% and (2.32 ± 0.01)%; Ee-Ce6-L exhibited strong singlet oxygen generation capacity; In vitro cell experiments demonstrated that Ee-Ce6-L promoted apoptosis in 5637 cells by increasing ROS production and reducing MMP, as well as by decreasing B-cell lymphoma-2 (Bcl-2) protein expression while increasing Bcl-2-associated X protein (Bax), cleaved poly ADP-ribose polymerase (cleaved PARP), and cleaved cystein-asparate protease-3 (cleaved Caspase-3) protein expression. Conclusion Ee-Ce6-L exhibits ROS-responsive release properties and synergistically inhibits 5637 cell proliferation and induces apoptosis through the combined effects of traditional Chinese medicine and phototherapy.

elemene  /  chlorin e6  /  liposome  /  bladder cancer  /  photodynamic therapy