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Michal Mauda-Havakuk,1,2 Natalie M Hawken,1 Joshua W Owen,1 Andrew S Mikhail,1 Matthew F Starost,3 Baktiar Karim,4 Paul G Wakim,5 Olga L Franco-Mahecha,1 Andrew L Lewis,6 William F Pritchard,1 John W Karanian,1 Bradford J Wood7 1Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA; 2Interventional Radiology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel; 3Division of Veterinary Resources, National Institutes of Health, Bethesda, MD, USA; 4National Cancer Institute, National Institutes of Health, Frederick, MD, USA; 5Biostatistics and Clinical Epidemiology Service, National Institutes of Health Clinical Center, Bethesda, MD, USA; 6Alchemed Bioscience Consulting Ltd, Stable Cottage, Monkton Lane, Farnham, Surrey, UK; 7Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institute of Biomedical Imaging and Bioengineering and National Cancer Institute Center for Cancer Research; National Institutes of Health, Bethesda, MD, USACorrespondence: Michal Mauda-Havakuk, Email michal.mh@gmail.comObjectives: Local and systemic immune responses evoked by locoregional therapies such as cryoablation are incompletely understood. The aim of this study was to characterize cryoablation-related immune response and the capacity of immune drugs to augment immunity upon cryoablation for the treatment of hepatocellular carcinoma (HCC) using a woodchuck hepatocellular carcinoma model.Materials and Methods: Twelve woodchucks chronically infected with woodchuck hepatitis virus and with hepatocellular carcinoma underwent imaging with contrast-enhanced CT. Partial cryoablation of tumors in three woodchucks was performed. Fourteen days after cryoablation, liver tissues were harvested and stained with H&E and TUNEL, and immune infiltrates were quantified. Peripheral blood mononuclear cells (PBMC) were collected from ablated and nonablated woodchucks, labeled with carboxyfluorescein succinimidyl ester (CFSE) and cultured with immune-modulating drugs, including a small PD-L1 antagonist molecule (BMS-202) and three TLR7/8 agonists (DSR 6434, GS-9620, gardiquimod). After incubation, cell replication and immune cell populations were analyzed by flow cytometry.Results: Local immune response in tumors was characterized by an increased number of CD3+ T lymphocytes and natural killer cells in the cryolesion margin compared to other tumor regions. T regulatory cells were found in higher numbers in distant tumors within the liver compared to untreated or control tumors. Cryoablation also augmented the systemic immune response as demonstrated by higher numbers of PBMC responses upon immune drug stimulation in the cryoablation group.Conclusions: Partial cryoablation augmented immune effects in both treated and remote untreated tumor microenvironments, as well as systemically, in woodchucks with HCC. Characterization of these mechanisms may enhance development of novel drug-device combinations for treatment of HCC.Plain Language Summary: The tumor microenvironment (TME) incorporates complex immune cell milieus. Tumor ablation can evoke an immune response in the tumor as well as systemically. Most reports, however, demonstrate modest immune activation.Better elucidation of the tumor microenvironment immune response to ablation was needed in order to promote an effective anti-tumoral response.In this study, the TME post ablation was analyzed in a multicompartmental fashion to better understand local immune response.In ablation margins, an abundance of anti-tumoral immune cells could be found. Distant tumors in ablated animals however had an increased number of regulatory immune cells.More effective response of peripheral blood mononuclear cells to stimulation of immune drugs was demonstrated post ablation.Strategies to augment more robust anti-tumoral immune responses might include targeting ablation margins with immune-stimulating agents and mitigating regulatory immune effects away from the ablation zone.Keywords: cryoablation, woodchuck, hepatocellular carcinoma, immune effect, tumor microenvironment, hepatitis B virus |
