RORγt agonist LYC-55716 potentiates IFN-α’s efficacy in hepatocellular carcinoma through enhancing cytotoxicity of Tc17 cells and infiltration of CD8+ T cells

While interferon-alpha (IFN-α) demonstrates potent antineoplastic activity against hepatocellular carcinoma (HCC), but many patients have a low response rate and may even develop resistance to it. It is necessary to find new strategies to reduce IFN-α resistance and improve its efficacy. RAR-related orphan receptor gamma t (RORγt) agonists exhibit dual immunomodulatory functions, demonstrating both immunosuppression-reducing and immune-activating properties. In this study, we demonstrated that the combination of the RORγt agonist-LYC-55716 and IFN-α significantly promoted cytotoxic T cell 17 (Tc17 cell) differentiation and interleukin-17a (I1-17a) expression through activation of the Akt/Stat3 signal pathway. The combination therapy markedly enhanced the tumoricidal activity of differentiated Tc17 cells against hepatoma carcinoma cells. Moreover, this therapeutic strategy showed superior antitumor efficacy in multiple HCC models while maintaining a favorable safety profile compared to single-agent treatment. Importantly, our findings revealed that the combination treatment significantly enhanced CD8⁺ T cells infiltration into tumor tissues. Moreover, our mechanistic studies revealed that the observed synergistic antitumor effect was mediated by enhanced CD8⁺ T cell tumor infiltration, which was facilitated by the C-X-C motif chemokine ligand 10 (Cxcl10)- C-X-C motif chemokine receptor 3 (Cxcr3) interaction. Collectively, these findings support a novel immunoregulatory strategy that leverages RORγt agonists to enhance the efficacy of IFN-α in HCC therapy.