[Knockdown of IL-1R8 augments the tumor-suppressive capacity of ex vivo expanded natural killer (NK) cells against hepatocellular carcinoma].

Objective Interleukin-1 receptor 8 (IL-1R8) is significantly upregulated in activated natural killer (NK) cells and serves as a critical negative regulator governing the anti-tumor immune activity of NK cells. This study aims to silence IL-1R8 expression in ex vivo expanded NK cells, and further elucidate the underlying molecular mechanism by which IL-1R8 modulates NK cell-mediated anti-tumor immunity against hepatocellular carcinoma (HCC). Methods IL-1R8 expression was knocked down in ex vivo expanded NK cells using lentivirus-derived IL-1R8 short hairpin RNA (shRNA), and the knockdown efficiency was verified by real-time quantitative PCR (qPCR) and Western blotting. Trypan blue staining was used to assess NK cell proliferation, while flow cytometry analyzed changes in the expression of major phenotypic receptors before and after IL-1R8 knockdown. A lactic dehydrogenase (LDH) release assay evaluated the in vitro cytotoxicity of NK cells against HCC cells, and ELISA measured the secretion levels of cytokines and chemokines during the killing process. A Huh7 xenograft mouse model was established to verify the in vivo anti-tumor therapeutic efficacy of IL-1R8-silenced NK cells. Immunohistochemical staining was performed to detect the intratumoral levels of NK cells within tumor tissues. Results Knockdown of IL-1R8 exerted no significant effects on the proliferation capacity and surface phenotypic characteristics of ex vivo expanded NK cells. Nevertheless, IL-1R8 downregulation remarkably potentiated the cytotoxicity of NK cells against HCC, and facilitated the secretion of multiple core anti-tumor cytokines and chemokines, including tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), C-C motif chemokine ligand 3 (CCL3) and C-X-C motif chemokine ligand 8 (CXCL8). In vivo animal experiments demonstrated that adoptive transfer of IL-1R8-knockdown NK cells significantly suppressed subcutaneous HCC tumor growth, meanwhile enhanced NK cell recruitment and infiltration in the tumor microenvironment. Conclusion Genetic ablation of IL-1R8 efficiently augments the anti-tumor effector function of NK cells against HCC both in vitro and in vivo, highlighting IL-1R8 as a promising target to improve the efficacy of NK cell-based therapies for cancer treatment.