Microenvironment and Immunology Cryotherapy with Concurrent CpG Oligonucleotide Treatment Controls Local Tumor Recurrence andModulates HER2/neu Immunity

Abstract

Percutaneous cryoablation is a minimally invasive procedure for tumor destruction, which can potentially initiate or amplify antitumor immunity through the release of tumor-associated antigens. However, clinically efficacious immunity is lacking and regional recurrences are a limiting factor relative to surgical excision. To understand the mechanism of immune activation by cryoablation, comprehensive analyses of innate immunity and HER2/neu humoral and cellular immunity following cryoablation with or without peritumoral CpG injection were conducted using two HER2/neuþ tumor systems in wild-type (WT), neu-tolerant, and SCID mice. Cryoablation of neuþ TUBO tumor in BALB/c mice resulted in systemic immune priming, but not in neutolerant BALB NeuT mice. Cryoablation of human HER2þ D2F2/E2 tumor enabled the functionality of tumorinduced immunity, but secondary tumors were refractory to antitumor immunity if rechallenge occurred during the resolution phase of the cryoablated tumor. A step-wise increase in local recurrence was observed inWT, neutolerant, and SCID mice, indicating a role of adaptive immunity in controlling residual tumor foci. Importantly, local recurrences were eliminated or greatly reduced in WT, neu tolerant, and SCID mice when CpG was incorporated in the cryoablation regimen, showing significant local control by innate immunity. For long-term protection, however, adaptive immunity was required because most SCID mice eventually succumbed to local tumor recurrence even with combined cryoablation and CpG treatment. This improved understanding of the mechanisms by which cryoablation affects innate and adaptive immunity will help guide appropriate combination of therapeutic interventions to improve treatment outcomes. Cancer Res; 74(19); 1–12. 2014 AACR. Introduction As immunotherapy becomes a mainstay in cancer therapy, attention is directed to immune constituents in the tumor microenvironment, particularly the modulation of their activities to enhance treatment outcomes. In parallel with this progress is the advancement in image guided percutaneous cryoablation that utilizes ultra-cold temperatures to precisely destroy cancers of the breast, prostate, kidney, liver, bone, lung, brain, and skin (1). Cryoablation directly induces necrosis by damaging cell membranes and organelles via the formation of ice crystals, and indirectly through osmotic stress and ischemia from thrombosis of the microvasculature (2). Compared with surgical resection, cryoablation is minimally invasive, places less stress on the body, allows for quicker recovery, and is less costly (3). In addition to debulking the tumor, the necrotic tissue becomes a rich reservoir of tumor-associated antigens that are cleared by antigen-presenting cells (APC), creating a unique opportunity to prime or boost systemic antitumor immune responses, which may afford increased survival (4). Induction of systemic immunity was initially observed in the 1970s when several patients had metastatic lesions regress following cryoablation of primary prostate tumors (5). Further support of "cryoimmunology" was linked to an increase in antibodies against DNA, RNA, and tumor cells in patients receiving palliative cryoablation for advanced cancer (6). More recently, a study following 20 patients with prostate cancer observed elevated levels of circulating inflammatory cytokines and cellular immunity after cryotherapy but found responses were transient and unable to prevent disease relapse (7). In a separate study, cryoablation ofmetastatic renal cell carcinoma resulted in elevated T cell and antibody (Ab) responses without affecting the growth of untreated foci (8). Although these results stimulated interest in the immunostimulatory potential of cryoablation, mechanisms leading to beneficial immunity have yet to be elucidated. Although enhanced immune priming after cryoablation has been described in a number of preclinical studies (9–11), others Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan. Karmanos Cancer Institute, Detroit, Michigan. Department of Urologic Oncology, Wayne State University School of Medicine, Detroit, Michigan. Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, Toledo, Ohio. Note: Supplementary data for this article are available at Cancer Research Online (http://cancerres.aacrjournals.org/). Corresponding Author: Wei-Zen Wei, Department of Oncology, Karmanos Cancer Institute, 4100 John Rd. PR04IM, Detroit, MI 48201. Phone: 313-578-4651; Fax: 313-578-4658; E-mail: weiw@karmanos.org doi: 10.1158/0008-5472.CAN-14-0501 2014 American Association for Cancer Research. Cancer Research www.aacrjournals.org OF1 Research. on April 15, 2017. © 2014 American Association for Cancer cancerres.aacrjournals.org Downloaded from Published OnlineFirst August 4, 2014; DOI: 10.1158/0008-5472.CAN-14-0501

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@inproceedings{Veenstra2014MicroenvironmentAI, title={Microenvironment and Immunology Cryotherapy with Concurrent CpG Oligonucleotide Treatment Controls Local Tumor Recurrence andModulates HER2/neu Immunity}, author={Jesse J. Veenstra and Heather M. Gibson and Peter Littrup and J. P. De Los Reyes and Michael L. Cher and Akira Takashima and Wei Wei}, year={2014} }