Blockade of the CLCF1-CNTFR axis enhances the efficacy of GPC3 CAR-T cell therapy in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) exhibits a profoundly immunosuppressive tumor microenvironment (TME) that limits the efficacy of immune checkpoint blockade and CAR-T cell therapy. In this study, we identified cardiotrophin-like cytokine factor 1 (CLCF1) as significantly upregulated in HCC and associated with poor prognosis and reduced response to immunotherapy. Accordingly, we engineered a GPC3-targeted CAR-T cell capable of self-secreting a soluble engineered CNTFR (eCNTFR) to locally neutralize CLCF1 within the TME. Compared with conventional GPC3 CAR-T cells, eCNTFR-armored GPC3 CAR-T cells exhibited enhanced cytotoxicity, increased cytokine production, improved functional persistence, and superior antitumor efficacy in vitro and in xenograft models. Mechanistically, eCNTFR-mediated blockade of the CLCF1-CNTFR axis suppressed STAT3 signaling and TGF-β production, thereby inhibiting tumor growth, stemness, and the formation of an immunosuppressive TME. These findings establish CLCF1 as a key tumor-promoting and immunosuppressive mediator in HCC and support eCNTFR-armored CAR-T cells as a promising therapeutic strategy for HCC immunotherapy.