Targeting of COPⅠ elicits CD8+ T cell-mediated anti-tumor immunity and suppresses growth of intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) possesses the immunosuppressive tumor microenvironment (TME) that limits the effectiveness of immunotherapy. Genetic alterations of the coat protein complex Ⅰ (COPⅠ) lead to STING activation and inflammatory immune response. This study aims to address whether targeting COPⅠ can be exploited as a strategy to elicit immune response and inhibit iCCA progression. Here, we demonstrated that the COPⅠ subunits were highly expressed in human and mouse iCCA tissues. Genetic and pharmacological inhibition of COPⅠ suppressed growth of the mouse autochthonous iCCAs driven by activated oncogenes. Disruption of COPⅠ increased T cell presence in tumor environment and elicited anti-tumor T cell response through activating STING- type-I interferon (IFN-I) pathway. Neutralizing CD8+ T cell or STING deletion efficiently counteracted the suppression of iCCA growth by targeting COPⅠ. In addition, the Wnt/β-catenin signaling was dramatically attenuated in tumor cells by STING activation in the context of COPⅠ disruption. Notably, targeting COPⅠ markedly potentiates the therapeutic efficacy of anti-PD-1 in suppressing iCCA growth. In conclusion, our study reveals that targeting COPⅠ effectively suppresses tumor growth by enhancing T cell presence and function in mouse iCCA. STING activation by COPⅠ inhibition dedicates the T cell control of iCCA growth. COPⅠ is a potential target for iCCA treatment.