Combination of Radiofrequency Ablation With Resiquimod to Treat Hepatocellular Carcinoma Via Inflammation of Tumor Immune Microenvironment and Suppression of Angiogenesis

Abstract

BackgroundRadiofrequency ablation (RFA) destroys tumors through hyperthermic injury, which induces the release of immunogenic intracellular substrates and damages associated molecular patterns (DAMPs) to evoke a systemic immune response, but its therapeutic effect is limited. This study aimed to combine RFA with an immunomodulator, resiquimod (R848), to enhance the RFA-induced antitumor immunity.MethodsWe performed RFA on subcutaneous tumors in immunocompetent mice and intraperitoneally injected R848 to observe the efficacy of the combination therapy. Our research investigated changes in the composition of tumor-infiltrating immune cells in primary and distant tumors by flow cytometry. Natural killer (NK) cell depletion experiment was applied to confirm the role of NK cell in the combination therapy. The expression levels of cytokines and chemokines were detected by real-time quantitative PCR. Immunohistochemical test was conducted to reveal tumor angiogenesis, tumor proliferation, and apoptosis after the different treatments.Results and ConclusionCompared with RFA or R848 monotherapy, the combination therapy significantly slowed the tumor growth, prolonged the survival time, and shrank the tumor-draining lymph nodes of tumor-bearing mice. The flow cytometry results showed that tumor-infiltrating immune cells, total T cells, the ratio of CD8+ T and NK cells to CD45+ cells, and functional NK cells were obviously increased after the combined treatment. Distal tumor growth was also suppressed, and the profile of tumor-infiltrating immune cells was remodeled, too. In addition, the additive effect of the combination therapy disappeared after NK cell depletion. Furthermore, immunohistochemical results verified that R848 inhibited tumor angiogenesis in murine liver cancer, and the combination therapy promoted tumor cell apoptosis. In conclusion, our data suggest that RFA combined with R848 stimulated a stronger antitumor immune response and effectively inhibited liver cancer progression in a NK cell-dependent manner. Meanwhile, we confirmed that R848 inhibited tumor angiogenesis and promoted apoptosis in murine liver cancer. Overall, this is a promising therapeutic strategy to improve the efficacy of RFA in the treatment of liver cancer and provides a novel option for combined thermal ablation and immunotherapy.

Spatiotemporal local and abscopal cell death and immune responses to histotripsy focused ultrasound tumor ablation

“…There has been longstanding interest in the capacity of ablation to activate tumor-directed immune responses. Measurable and occasionally abscopal anti-tumor immune responses have been observed with cryoablation, radiofrequency ablation and radiation, largely when used in combination with immunomodulatory agents like CpG or pro-inflammatory cytokines (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). We recently reported that histotripsy, a non-thermal mode of mechanical FUS ablation (32-36), stimulates potent local and abscopal CD8+ T cell infiltration and tumor inhibition as monotherapy; using murine models of melanoma and hepatocellular carcinoma, we observed that this effect can enhance checkpoint inhibition immunotherapy (37).…”

“…There is great interest in developing ablative therapies to trigger systemic anti-tumor immune responses that could augment the efficacy of cancer immunotherapy (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). By initiating immunogenic cell death pathways (e.g., necroptosis, pyroptosis) that release tumor-specific antigens within the context of pro-inflammatory danger signals, ablation could initiate the cancer immunity cycle of antigen presentation and adaptive immune stimulation (14).…”

A Booster for Radiofrequency Ablation: Advanced Adjuvant Therapy via In Situ Nanovaccine Synergized with Anti-programmed Death Ligand 1 Immunotherapy for Systemically Constraining Hepatocellular Carcinoma

“…The method for preparing single-cell suspensions was described previously . Briefly, mice were sacrificed 14 days after different treatments, and the tumor was cut into pieces, digested, and resuspended.…”

Mechanisms and therapeutic strategies to combat the recurrence and progression of hepatocellular carcinoma after thermal ablation

“… 71 In addition, RFA, combined with the immunomodulator Resiquimod (R848), can stimulate a stronger anti-tumor immune response, inhibit angiogenesis, promote cell apoptosis, and effectively inhibit the progression of HCC in mice in an NK cell-dependent manner. 133 Adoptive cellular therapy (ACT) has demonstrated great potential in immunotherapy tumors. ACT refers to extracting T cells from patients, culture, and modification in vitro , followed by reinfusion into the patient to destroy tumor cells.…”