Mitochondria-targeting polymer cLipG/CuET activates the cGAS/STING pathway to enhance cholangiocarcinoma immunotherapy.

[BACKGROUND] The remodeling of extracellular matrix often fails chemotherapeutic agents to fight intrahepatic cholangiocarcinoma (ICC). The cGAS/STING pathway can trigger the innate immune response to obtain better immunotherapeutic outcomes.

[RESULTS] A cLipG/CuET nanocomposite was designed and synthesized based on glycyrrhizic acid (GA) and copper diethyldithiocarbamate (CuET). GA can open mitochondrial permeability transition pores (MPTPs), allowing Cu (II) to interrupt mitochondrial function through copper toxicity. By activating the cGAS-STING signaling pathway in macrophages, this mitochondrial-targeting polymer (cLipG/CuET) significantly boosted the production of mitochondrial reactive oxygen species (mtROS), and promoted the escape of damaged mitochondrial DNA (mtDNA) from ICC cells. Consequently, M1 polarization of cancer-associated macrophages enhanced the immune response against ICC. In the mouse model, the intravenous administration of cLipG/CuET transformed the ICC from "cold" into "hot".

[CONCLUSIONS] With a high biosafety, cLipG/CuET exerted a synergistic effect on the immune checkpoint inhibitor αCTLA-4 against ICC, and their combination provided a new therapeutic strategy.