Building a New Therapeutic Paradigm for Hepatocellular Cancer by Dissecting the Interaction between Radiofrequency Ablation, Chemotherapy, and Immunotherapy

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Hepatocellular cancer (HCC) remains one of the deadliest cancers with limited clinical options. Due of life style choices, living conditions, and/or environmental elements, risk factors for the development of HCC cause the increased incidence in military service members, veterans, and their families with 10-fold higher than the general population. Radiofrequency ablation (RFA) has emerged as a first line treatment option for patients with HCC. When combined with modern imaging, RFA can be performed percutaneously or laparoscopically. Image-guided RFA has the following significant advantages: lower morbidity, minimized physiologic insult of surrounding tissues, reduced cost, short hospitalization time, and intra-procedural visualization for precise targeting. However, incomplete ablation, tumor recurrence, and inferior outcomes persist, revealing that rational combination with other therapeutic strategies is needed to more effectively treat HCC. Breakthroughs in cancer immunotherapy offer potential promise for HCC treatment, but no approaches have been translated into clinical application. In situ RFA capably destroys tumor cells to release substantial antigens that might modulate antitumor immunity. However, the resultant therapeutic immune response by RFA alone is too modest to destroy established tumors. This is because tumors develop different mechanisms to induce profound immunotolerance in the tumor microenvironment. Therefore, overcoming tumor-induced immunotolerance is critically important for RFA-liberated antigens to prime powerful antitumor immune response. Recently, the investigators created a novel murine model. This model mimics human HCC initiation and progression, and reflects typical features of human HCC including tumor-induced immunotolerance. Using this model, they have first demonstrated that FDA-approved chemotherapeutic agent, sunitinib, prevents tumor antigen-specific immunotolerance and allows effective immunotherapy resulting in regression of established tumors in HCC, which is mechanistically associated with suppression of Tregs. By using nanotechnology to develop nanoliposome-loaded C6-ceramide (LipC6), they demonstrated that LipC6 not only exerts tumoricidal effect but also prevents tumor-induced immunotolerance by modulating tumor-associated macrophages (TAMs). They have also found a critical role of immune checkpoints in HCC-induced profound immunosuppression, and demonstrated that Ab-mediated blockade of PD-1 has a significant immunotherapeutic effect in the experimental- HCC treatment. In addition, the investigators have successfully modified a human cardiac RFA generator, and they are now able to conduct HCC tumor ablations in this novel murine model. The overall objective of the proposed study is to develop and define the mechanisms of RFA-integrated chemo-immunotherapy against HCC. They will achieve this goal via two specific aims: 1) Determine the therapeutic antitumor immune response and elucidate the underlying mechanisms in tumor bearing mice treated with sunitinib, LipC6, RFA, and their combination; 2) Determine the dominant inhibitory immune checkpoint pathways mediating immune resistance in HCC and develop a rational combination therapy with RFA for HCC control. Completion of the proposed study is expected to generate new and clinically feasible therapeutic strategies which can be translated into clinical practice for the treatment of this deadly cancer.