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The future of cryoablation: An abscopal effect
Cryobiology xxx (xxxx) xxx
Contents lists available at ScienceDirect
Cryobiology journal homepage: http://www.elsevier.com/locate/cryo
Review
The future of cryoablation: An abscopal effect Jibing Chen a, Wei Qian a, Feng Mu a, Lizhi Niu a, Duanming Du b, *, Kecheng Xu a, ** a b
Fuda Cancer Hospital, Jinan University, Guangzhou, China Intervention Dept. of Shenzhen Second People’s Hospital, Shenzhen, 518035, China
A R T I C L E I N F O
A B S T R A C T
Keywords: Cryosurgery Immunotherapy Granulocyte-macrophage colony-stimulating factor Dendritic cells Natural killer cells Hydrogen
Cryoablation has become a popular modality to treat a variety of malignant tumors in solid organs and soft tissues. In the future, the use of cryoablation should focus on its abscopal effect. The present review discusses the increased immune response triggered by cryoablation alone or by cryoablation combined with immunotherapies, which can improve the immune response and limit immunosuppression. First, cryoablative techniques should be improved to increase the area of necrosis and reduce the area of apoptosis. Second, cryoablation should be combined with immunotherapies, for example, cyclophosphamide, natural killer cells, granulocyte monocyte colony stimulating factor (GM-CSF), cytotoxic T lymphocyte-associated antigen (CTLA)-4, and programmed death receptor 1 (PD)-1 inhibitors. Cryoablation could also be combined with Hydrogen gas molecules, which were shown recently to stimulate peroxisome proliferator activated receptor gamma coactivator (PGC)-1α, thereby promoting mitochondrial function, which might rescue exhausted CD8þ T cells, leading to prolonged progression-free survival and overall survival of patients with advanced colorectal cancer.
1. Introduction
2. Methods that could increase the abscopal effect
Cryoablation, as an alternative to surgical resection, is used widely to treat localized malignant tumors in the breast, liver, lung, kidney, prostate, and soft tissue. This modality has become even more popular because of the development of imaging-guiding techniques and third generation units [41]. The abscopal immune-regulatory effects of cry oablation have been recognized since the 1970s [1,37], which can affect, or potentially eliminate, metastatic tumors. This effect was referred to as cryo-immunotherapy. However, cryoablation alone may not induce an abscopal effect and might require specific conditions to display its effect [5,29,30]. Despite this, clinical and preclinical data indicate that compared with the weaker immunomodulatory effects observed for other thermal ablation techniques, the immune in teractions of cryoablation were particularly apparent [15]. Therefore, a comprehensive study of the long-term efficacy and abscopal effects of cryoablation in the future would be very valuable. In the present review, we discuss the future development of cryoablation from two aspects: The enhancement of immune responses by cryoablation and the combination of cryoablation with immunotherapies, thereby improving immunosti mulation and limiting immunosuppression.
2.1. Enhancement of cryoimmunity by improving ablative technology Apoptosis and necrosis are the primary mechanisms of tumor cell death and have a significantly different impact on cryoimmunity [29]. In a small area around the probe, cryoablation uses expanding special gases to induce necrotic cell death by inducing an ice ball. Necrotic cell death results in the release of heat shock proteins (HSPs), damage associated molecular patterns (DAMPs, antigens, and intracellular organelles [36]. DAMPs can activate the nuclear factor kappa B (NF-κB) pathway, inducing expression of co-stimulatory CD80/86 molecules on DCs. An tigens presented on major histocompatibility complex molecules on DCs display co-stimulators that stimulate T-cells to promote a systemic im mune response, resulting in the so-called “in-vivo dendritic cell vac cine”. Cryoablation produces a potent immunostimulatory response, as shown by the significantly higher levels of NF-κB, serum interleukin (IL)-1, IL-6, and tumor necrosis factor-α post-ablation [4,7]. However, the sublethal temperatures in the peripheral area of the ice ball induce apoptotic cell death. Apoptotic cell death also results in the release of antigens that are picked up by DCs; however, this does not normally include DAMPs. In the absence of phagocytosed DAMPS, activation of
* Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (D. Du), [email protected] (K. Xu). https://doi.org/10.1016/j.cryobiol.2020.02.010 Received 30 October 2019; Received in revised form 20 February 2020; Accepted 21 February 2020 Available online 22 February 2020 0011-2240/© 2020 Elsevier Inc. All rights reserved.
Please cite this article as: Jibing Chen, Cryobiology, https://doi.org/10.1016/j.cryobiol.2020.02.010
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the NF-κB pathway does occur and CD80/CD86 expression is not induced. In the absence of these co-stimulators, the immune response is suppressed by T cell anergy or clonal deletion. Therefore, the cryotherapy-induced systemic immune response seems to rely on necrotic cell death. Thus, both immunostimulatory and immunosuppressive effects are induced by cryoablation alone. The balance between necrosis and apoptosis, which can vary over time, determines whether stimulation or suppression prevails [31]. Therefore, cryoablative techniques should be improved to increase the area of ne crosis and reduce the area of apoptosis. Recent research has focused on two approaches to effect better control of this procedure. The first method comprises patient-specific computational modeling that predicts the temperature isotherms in the ice ball and allows esti mation of the tissue volume that reaches temperatures below 40 � C. The speed and accuracy of these predictions have been enhanced significantly by improved computational method and imaging inputs into the models. The imaging inputs allow the surgeon to visualize the 3D geometry of the frozen region with contours of 0.5 � C, thereby producing real-time feedback during ablation [27]. The second approach uses molecular adjuvants that increase tissue cryosensitivity at the periphery of the ice ball [32]. The solid phase or crystalline ice are modified using thermophysical adjuvants, including salts, antifreeze proteins, and some amino acids, which cause additional direct cell injury because of the presence of ice crystals. The development of targeted delivery methods that deliver the required dose, but do not induce toxicity to the surrounding normal tissue, remains a major challenge in this approach.
cyclophosphamide was significantly more effective at inducing systemic antitumor immunity, achieving a curative effect in a proportion of the mice that had established metastatic disease that was resistant to tumor rechallenge. Lymphocytes isolated from the cured mice comprised an enhanced population of interferon-gamma producing, tumor-specific T cells. Moreover, this antitumor immunity could be transferred to naive recipients. CD8þ cells cell depletion impaired the adoptive transfer of antitumor immunity significantly. In addition, cyclophosphamide treatment combined with cryoablation correlated with a significant decrease in the ratio of effector to regulatory CD4þ T cells [22]. 2.4. Dendritic cell therapy DCs are antigen presenting cells comprising the first line of defense that can take up, process, and present tumor antigens. Upon activation by infection, the expression of co-stimulators in DCs increases, which then activate a larger lymphocyte response [22]. Imiquimod, a topically-applied toll-like receptor (TLR)7 agonist, stimulates immature DCs to express surface co-stimulators, including CD80 and CD86. Imiquimod-activated DCs go on to trigger Th1 cell immunity. The administration of cryoablation combined with topical Imiquimod resulted in significant protection against rechallenge in 90% of cases, compared with 30% resulting from cryotherapy alone. Cryotherapy and Imiquimod can work together for synergy to treat some kind of tumor [35]. Synthetic CpG-oligodeoxynucleotides (CpG ODNs) have been con structed from bacterial DNA. DCs activated by TLR9 in response to CpGs secrete IFN-α, which induces clumping and migration of more DCs. B cells secrete Th1 inducing mediators, resist programmed cell death, and increase their expression of co-stimulators in response to stimulation by TLRs activated by CpGs. Thus, the innate immune response can be stimulated by the application of artificial CpG ODNs. CpG ODNs administered peritumorally following local destructive therapy increased DC activation and improved the tumor specific CD8þ T cell response. Furthermore, treatment with a combination of CpG ODNs and cryoablation caused existing secondary tumors to regress in 40% of mice and protected them completely against outgrowth of local recurrence at 15 days after treatment [28]. Immature DCs alone injected intratumorally enhanced the prolifer ation of CD8þ T cells. In addition, ex vivo immature DCs combined with cryotherapy administration resulted in significantly prolonged survival after amputation of the foot bearing the primary tumor and after rechallenge [6,16,21]. We have studied the beneficial effects of combining ex vivo DC infusion with cryoablative therapy. In liver, lung, breast, and pancreatic cancer, and the survival of patients who received DCs/CIK (cytokine-induced killers) infusion was longer compared with that induced by cryoablation alone [23,34,42].
2.2. Granulocyte macrophage colony-stimulating factor (GM-CSF) GM-CSF stimulates DCs to display tumor antigens, making GM-CSFs useful for cancer immunotherapy. A combination of cryoablation and GM-CSF could enhance the antitumor effects. A study in a murine sub cutaneous glioma model showed that the combined therapy could syn ergistically improve specific anti-tumor immunity, including increased activation and numbers of DCs. In addition, Th1 cell secretion of inter feron (IFN)-γ in the mouse spleen increased and CD8þT cells’ cytolytic activity produced a significantly increased cytotoxic effect on malignant cells [40]. A pilot clinical study in six patients with renal cell cancer showed that percutaneous cryoablation of lung metastasis in combination with aerosolized GM-CSF could induce systemic cellular and humoral im mune responses. In four of six patients, the authors observed specific in vitro antitumor antibody responses, tumor-specific cytotoxic T lympho cytes, and enhanced production of Th1 cytokines. Importantly, the clinical responses seemed to be associated with the size of the humoral and cellular antitumor responses [38]. However, a clinical study showed that cryoablation plus intralesional GM-CSFs correlated with increased HSP70 levels after therapy; however, no significant induction of anti-tumor T cell responses was detected [17].
2.5. Natural killer cell therapy
2.3. Depletion of regulatory T cells (Tregs)
NK are non-specific killer cells that belong to the innate immune system, playing important roles in the early stages of the fight against cancer [14]. Increased understanding of the functions of NK cells together with progress in NK cell biology, have shown promising anti-tumor effects on various cancers resulting from adoptive NK cell transfer. In contrast to cytotoxic T cells or other immunocytes identified in the target, NK cells are trained to recognize “non-self” histocompat ibility antigens on cell surfaces via killer cell immunoglobulin-like (KIR) receptors. The production of immune-active cytokines by NK cells makes them attractive tools for immunotherapy. Cryoablation combined with allogeneic NK cells produced a synergistic effect, resulting in enhanced immune function and improved quality of life of the patients. Two groups of patients with hepatocellular carcinoma underwent cryo-NK and cryo treatment alone, in which cryo-NK showed a survival benefit [24,25].
A subset of CD4þ T cells, termed regulatory T cells (Tregs), decrease the capacity of a tumor-bearing host to mount an immune response against tumor antigens. Tregs express the transcription factor forkhead box P3 (FOXP3) and CD25, and can potently suppress immunity via the inhibition of natural killer (NK) cells and cytotoxic T lymphocytes. Tregs are also believed to function in tolerance to self-antigens and tumors [17]. Directly targeting CD25þFOXP3þ Tregs for depletion represents a more direct method of overcoming immune regulation. In addition, this inhibitory mechanism can be diminished by the administration of anti-CD25 antibodies [8]. The anti-cancer drug cyclophosphamide depletes Tregs selectively. In a mouse model of metastatic colon cancer, compared with surgical excision or cauterization, cryoablation combined with 2
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Fig. 1. Currently identified cryoablation-associated immunotherapies. The 7 numbers in the figure represent the 7 methods mentioned in the article that can enhance the cryoimmunology, that is, 7 cryo-immunotherapies. Granulocyte-macrophage colony-stimulating factor, GM-CSF; Natural killer cells, NK; Te, effector T cell; CTLA-4, cytotoxic T lymphocyte-associated antigen-4; PD-1, programmed death receptor 1; Treg, regulatory T cell; Cy, low dose cyclophosphamide.
2.6. Immunological checkpoint inhibitors
2.7. Hydrogen gas therapy
Cytotoxic T lymphocyte-associated antigen (CTLA)-4 binds to cos timulatory B7 molecules to inhibit T cell stimulation competitively, which promotes T cell anergy. Anti-CTLA-4 antibodies, such as Ipili mumab and tremelimumab, have achieved some success in relieving this regulatory bottleneck. Similarly, an inhibitory receptor found on T cells, programmed death receptor (PD)-1, is activated by programmed cell death 1 ligand (PD-L1), which inhibits T cell function, thereby inducing apoptosis. Anti-PD-1 drugs, such as Avelumab, Durvalumab, Nivolumab, and Pembrolizumab, have been approved for the treatment of many malignancies. Thus, the ability of tumors to evade the host immune system may be associated with the CTLA-4 and PD-1 pathways, making them prime targets for immunomodulation, especially in combination with ablation. The combination of anti-CTLA-4 therapy with cryoablation signifi cantly increased the number of effector T-cells in the cryoablated tissue. In addition to efficient freezing-induced ablation and reduction of the primary tumor, a second tumor (implanted after-cryoablation) dis played a strong CD8þ T cell response [39]. Two recent clinical studies supported the feasibility of combined cryoablation and anti-CTLA-4 treatments. Eleven patients with hepatocellular carcinoma were treated with the CTLA-4 inhibitor tremelimumab with cryoablation. The results showed that in some patients, CD8þ T-cells accumulated in their tumor tissue, which could enhance the therapeutic effect [18]. In addition, the combination of cryoablation with ipilimumab was assessed for its feasibility in treating breast cancer. The results showed that the combination triggered a systemic immune reaction in the patients [26]. At 1 week after cryoablation, circulating PD-L1 and intratumoral PD-L1 levels had increased significantly, which was associated with poor prognosis after cryoablation [43]. These results suggested cryoablation combined with systemic PD-1 inhibitor therapy would be reasonable. Further studies are necessary to determine the reversal effect of immune cell exhaustion via anti-PD-1 therapy [2].
Hydrogen inhalation has been found to have an adjuvant effect in the clinical treatment of various advanced cancers (e.g. gall bladder cancer [11,13] and nasopharyngeal cancer [9]), especially lung cancer [10,12]. Cytotoxic CD8þT cells become exhausted after continued stimulation by carcinoma cells, thus losing their proliferative, cytokine production, or cytotoxic capabilities. Exhausted CD8þ T cells show dysfunctional mitochondria, resulting from inactivation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and subse quently express immune checkpoint inhibitors, including PD-1 [33]. Recently, hydrogen was demonstrated to stimulate PGC-1α [13,20], leading to enhanced mitochondrial function [19], which might rescue exhausted CD8þ T cells. A prospective study of 55 patients suffering from stage IV colorectal carcinoma indicated that hydrogen treatment for 3 h/day resulted in decreased levels of exhausted terminal PD-1þCD8þ T cells and increased levels of active terminal PD-1-CD8þ T cells. This hydrogen gas treatment-associated effect correlates significantly with enhanced progression-free and overall survival [3]. In 2019, another prospective study of patients (n ¼ 82) with multiple stage III and IV cancers showed a significant benefit after 4 weeks of hydrogen inhalation. Hydrogen treatment for 4 weeks could decrease the levels of tumor markers and control tumor growth; the most obvious effect were on lung cancer, and the effect on patients with stage III disease was better than that on pa tients with stage IV disease [12]. Based on these observations, it is reasonable to propose that the inhalation of hydrogen gas before and after cryoablation could provide improved prognosis by reversing the imbalance toward PD-1þCD8þ T cells. 3. Discussion and conclusion Cryoablation is currently the only method that preserves the immunogenicity of tumor antigens and may cause abscopal effects. For more patients to enjoy the added benefit of this therapy, it is necessary to induce an immune response instead of immune tolerance. Numerous 3
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known immunotherapies might be combined with cryotherapy to constitute cryo-immunotherapy (Fig. 1). The main limitation of this combined therapy might be the choice of therapies based on immune function assessment.
[21] A.M. Krieg, Therapeutic potential of Toll-like receptor 9 activation, Nat. Rev. Drug Discov. 5 (2006) 471–484. [22] M.Y. Levy, A. Sidana, W.H. Chowdhury, S.B. Solomon, C.G. Drake, R. Rodriguez, E. J. Fuchs, Cyclophosphamide unmasks an antimetastatic effect of local tumor cryoablation, J. Pharmacol. Exp. Therapeut. 330 (2009) 596–601. [23] M. Lin, S. Liang, F. Jiang, J. Xu, W. Zhu, W. Qian, Y. Hu, Z. Zhou, J. Chen, L. Niu, K. Xu, Y. Lv, 2003-2013, a valuable study: autologous tumor lysate-pulsed dendritic cell immunotherapy with cytokine-induced killer cells improves survival in stage IV breast cancer, Immunol. Lett. 183 (2017) 37–43. [24] M. Lin, S. Liang, X. Wang, Y. Liang, M. Zhang, J. Chen, L. Niu, K. Xu, Cryoablation combined with allogenic natural killer cell immunotherapy improves the curative effect in patients with advanced hepatocellular cancer, Oncotarget 8 (2017) 81967–81977. [25] M. Lin, S.Z. Liang, X.H. Wang, Y.Q. Liang, M.J. Zhang, L.Z. Niu, J.B. Chen, H.B. Li, K.C. Xu, Clinical efficacy of percutaneous cryoablation combined with allogenic NK cell immunotherapy for advanced non-small cell lung cancer, Immunol. Res. 65 (2017) 880–887. [26] H.L. McArthur, A. Diab, D.B. Page, J. Yuan, S.B. Solomon, V. Sacchini, C. Comstock, J.C. Durack, M. Maybody, J. Sung, A. Ginsberg, P. Wong, A. Barlas, Z. Dong, C. Zhao, B. Blum, S. Patil, D. Neville, E.A. Comen, E.A. Morris, A. Kotin, E. Brogi, Y.H. Wen, M. Morrow, M.E. Lacouture, P. Sharma, J.P. Allison, C. A. Hudis, J.D. Wolchok, L. Norton, A pilot study of preoperative single-dose ipilimumab and/or cryoablation in women with early-stage breast cancer with comprehensive immune profiling, Clin. Canc. Res. 22 (2016) 5729–5737. [27] L. Ratanaprasatporn, N. Sainani, J.B. Duda, A. Aghayev, S. Tatli, S.G. Silverman, P. B. Shyn, Imaging findings during and after percutaneous cryoablation of hepatic tumors, Abdom Radiol (NY) 44 (2019) 2602–2626. [28] P. Redondo, J. del Olmo, A. Lopez-Diaz de Cerio, S. Inoges, M. Marquina, I. Melero, M. Bendandi, Imiquimod enhances the systemic immunity attained by local cryosurgery destruction of melanoma lesions, J. Invest. Dermatol. 127 (2007) 1673–1680. [29] M.S. Sabel, Cryo-immunology: a review of the literature and proposed mechanisms for stimulatory versus suppressive immune responses, Cryobiology 58 (2009) 1–11. [30] M.S. Sabel, A. Arora, G. Su, A.E. Chang, Adoptive immunotherapy of breast cancer with lymph node cells primed by cryoablation of the primary tumor, Cryobiology 53 (2006) 360–366. [31] M.S. Sabel, G. Su, K.A. Griffith, A.E. Chang, Rate of freeze alters the immunologic response after cryoablation of breast cancer, Ann. Surg Oncol. 17 (2010) 1187–1193. [32] A.V. Sarabanda, T.J. Bunch, S.B. Johnson, S. Mahapatra, M.A. Milton, L.R. Leite, G. K. Bruce, D.L. Packer, Efficacy and safety of circumferential pulmonary vein isolation using a novel cryothermal balloon ablation system, J. Am. Coll. Cardiol. 46 (2005) 1902–1912. [33] N.E. Scharping, A.V. Menk, R.S. Moreci, R.D. Whetstone, R.E. Dadey, S.C. Watkins, R.L. Ferris, G.M. Delgoffe, The tumor microenvironment represses T cell mitochondrial biogenesis to drive intratumoral T cell metabolic insufficiency and dysfunction, Immunity 45 (2016) 374–388. [34] L.C. Schmeel, F.C. Schmeel, C. Coch, I.G. Schmidt-Wolf, Cytokine-induced killer (CIK) cells in cancer immunotherapy: report of the international registry on CIK cells (IRCC), J. Canc. Res. Clin. Oncol. 141 (2015) 839–849. [35] K.S. Shaw, G.H. Nguyen, M. Lacouture, L. Deng, Combination of imiquimod with cryotherapy in the treatment of penile intraepithelial neoplasia, JAAD Case Rep 3 (2017) 546–549. [36] R. Slovak, J.M. Ludwig, S.N. Gettinger, R.S. Herbst, H.S. Kim, Immuno-thermal ablations - boosting the anticancer immune response, J Immunother Cancer 5 (2017) 78. [37] S. Tanaka, Immunological aspects of cryosurgery in general surgery, Cryobiology 19 (1982) 247–262. [38] A. Thakur, P. Littrup, E.N. Paul, B. Adam, L.K. Heilbrun, L.G. Lum, Induction of specific cellular and humoral responses against renal cell carcinoma after combination therapy with cryoablation and granulocyte-macrophage colony stimulating factor: a pilot study, J. Immunother. 34 (2011) 457–467. [39] R. Waitz, S.B. Solomon, E.N. Petre, A.E. Trumble, M. Fasso, L. Norton, J.P. Allison, Potent induction of tumor immunity by combining tumor cryoablation with antiCTLA-4 therapy, Cancer Res 72 (2012) 430–439. [40] H. Xu, Q. Wang, C. Lin, Z. Yin, X. He, J. Pan, G. Lu, S. Zhang, Synergism between cryoablation and GM-CSF: enhanced immune function of splenic dendritic cells in mice with glioma, Neuroreport 26 (2015) 346–353. [41] K.C. Xu, N.N. Kopper, L.Z. Niu, Modern Cryosurgery for Cancer, World Sci Pub, 2012. [42] Y. Yuanying, N. Lizhi, M. Feng, W. Xiaohua, Z. Jianying, Y. Fei, J. Feng, H. Lihua, C. Jibing, L. Jialiang, X. Kecheng, Therapeutic outcomes of combining cryotherapy, chemotherapy and DC-CIK immunotherapy in the treatment of metastatic nonsmall cell lung cancer, Cryobiology 67 (2013) 235–240. [43] Z. Zeng, F. Shi, L. Zhou, M.N. Zhang, Y. Chen, X.J. Chang, Y.Y. Lu, W.L. Bai, J. H. Qu, C.P. Wang, H. Wang, M. Lou, F.S. Wang, J.Y. Lv, Y.P. Yang, Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma, PloS One 6 (2011), e23621.
Declaration of competing interest None. Acknowledgments Not applicable. References [1] R.J. Ablin, Cryoimmunotherapy, Br. Med. J. 3 (1972) 476. [2] L.C. Adam, J. Raja, J.M. Ludwig, A. Adeniran, S.N. Gettinger, H.S. Kim, Cryotherapy for nodal metastasis in NSCLC with acquired resistance to immunotherapy, J Immunother Cancer 6 (2018) 147. [3] J. Akagi, H. Baba, Hydrogen gas restores exhausted CD8þ T cells in patients with advanced colorectal cancer to improve prognosis, Oncol. Rep. 41 (2019) 301–311. [4] S. Basu, R.J. Binder, R. Suto, K.M. Anderson, P.K. Srivastava, Necrotic but not apoptotic cell death releases heat shock proteins, which deliver a partial maturation signal to dendritic cells and activate the NF-kappa B pathway, Int. Immunol. 12 (2000) 1539–1546. [5] J.G. Baust, A.A. Gage, The molecular basis of cryosurgery, BJU Int. 95 (2005) 1187–1191. [6] B. Behm, P. Di Fazio, P. Michl, D. Neureiter, R. Kemmerling, E.G. Hahn, D. Strobel, T. Gress, D. Schuppan, T.T. Wissniowski, Additive antitumour response to the rabbit VX2 hepatoma by combined radio frequency ablation and toll like receptor 9 stimulation, Gut 65 (2016) 134–143. [7] V. Bottero, S. Withoff, I.M. Verma, NF-kappaB and the regulation of hematopoiesis, Cell Death Differ. 13 (2006) 785–797. [8] S. Brode, A. Cooke, Immune-potentiating effects of the chemotherapeutic drug cyclophosphamide, Crit. Rev. Immunol. 28 (2008) 109–126. [9] J. Chen, X. Kong, F. Mu, T. Lu, D. Du, K. Xu, Hydrogen-oxygen therapy can alleviate radiotherapy-induced hearing loss in patients with nasopharyngeal cancer, Ann. Palliat. Med. 8 (2019) 746–751. [10] J. Chen, F. Mu, T. Lu, D. Du, K. Xu, Brain metastases completely disappear in nonsmall cell lung cancer using hydrogen gas inhalation: a case report, OncoTargets Ther. 12 (2019) 11145–11151. [11] J. Chen, F. Mu, T. Lu, Y. Ma, D. Du, K. Xu, A gallbladder carcinoma patient with pseudo-progressive remission after hydrogen inhalation, OncoTargets Ther. 12 (2019) 8645–8651. [12] J.B. Chen, X.F. Kong, Y.Y. Lv, S.C. Qin, X.J. Sun, F. Mu, T.Y. Lu, K.C. Xu, Real world survey" of hydrogen-controlled cancer: a follow-up report of 82 advanced cancer patients, Med. Gas Res. 9 (2019) 115–121. [13] J.B. Chen, Z.B. Pan, D.M. Du, W. Qian, Y.Y. Ma, F. Mu, K.C. Xu, Hydrogen gas therapy induced shrinkage of metastatic gallbladder cancer: a case report, World J Clin Cases 7 (2019) 2065–2074. [14] M. Cheng, Y. Chen, W. Xiao, R. Sun, Z. Tian, NK cell-based immunotherapy for malignant diseases, Cell. Mol. Immunol. 10 (2013) 230–252. [15] K.F. Chu, D.E. Dupuy, Thermal ablation of tumours: biological mechanisms and advances in therapy, Nat. Rev. Canc. 14 (2014) 199–208. [16] M.H. den Brok, R.P. Sutmuller, S. Nierkens, E.J. Bennink, L.W. Toonen, C. G. Figdor, T.J. Ruers, G.J. Adema, Synergy between in situ cryoablation and TLR9 stimulation results in a highly effective in vivo dendritic cell vaccine, Cancer Res 66 (2006) 7285–7292. [17] E. Domingo-Musibay, J.M. Heun, W.K. Nevala, M. Callstrom, T. Atwell, E. Galanis, L.A. Erickson, S.N. Markovic, Endogenous heat-shock protein induction with or without radiofrequency ablation or cryoablation in patients with stage IV melanoma, Oncol. 22 (2017) 1026–e1093. [18] A.G. Duffy, S.V. Ulahannan, O. Makorova-Rusher, O. Rahma, H. Wedemeyer, D. Pratt, J.L. Davis, M.S. Hughes, T. Heller, M. ElGindi, A. Uppala, F. Korangy, D. E. Kleiner, W.D. Figg, D. Venzon, S.M. Steinberg, A.M. Venkatesan, V. Krishnasamy, N. Abi-Jaoudeh, E. Levy, B.J. Wood, T.F. Greten, Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma, J. Hepatol. 66 (2017) 545–551. [19] C. Handschin, B.M. Spiegelman, Peroxisome proliferator-activated receptor gamma coactivator 1 coactivators, energy homeostasis, and metabolism, Endocr. Rev. 27 (2006) 728–735. [20] N. Kamimura, H. Ichimiya, K. Iuchi, S. Ohta, Molecular hydrogen stimulates the gene expression of transcriptional coactivator PGC-1alpha to enhance fatty acid metabolism, NPJ Aging Mech Dis 2 (2016) 16008.
4
Contents lists available at ScienceDirect
Cryobiology journal homepage: http://www.elsevier.com/locate/cryo
Review
The future of cryoablation: An abscopal effect Jibing Chen a, Wei Qian a, Feng Mu a, Lizhi Niu a, Duanming Du b, *, Kecheng Xu a, ** a b
Fuda Cancer Hospital, Jinan University, Guangzhou, China Intervention Dept. of Shenzhen Second People’s Hospital, Shenzhen, 518035, China
A R T I C L E I N F O
A B S T R A C T
Keywords: Cryosurgery Immunotherapy Granulocyte-macrophage colony-stimulating factor Dendritic cells Natural killer cells Hydrogen
Cryoablation has become a popular modality to treat a variety of malignant tumors in solid organs and soft tissues. In the future, the use of cryoablation should focus on its abscopal effect. The present review discusses the increased immune response triggered by cryoablation alone or by cryoablation combined with immunotherapies, which can improve the immune response and limit immunosuppression. First, cryoablative techniques should be improved to increase the area of necrosis and reduce the area of apoptosis. Second, cryoablation should be combined with immunotherapies, for example, cyclophosphamide, natural killer cells, granulocyte monocyte colony stimulating factor (GM-CSF), cytotoxic T lymphocyte-associated antigen (CTLA)-4, and programmed death receptor 1 (PD)-1 inhibitors. Cryoablation could also be combined with Hydrogen gas molecules, which were shown recently to stimulate peroxisome proliferator activated receptor gamma coactivator (PGC)-1α, thereby promoting mitochondrial function, which might rescue exhausted CD8þ T cells, leading to prolonged progression-free survival and overall survival of patients with advanced colorectal cancer.
1. Introduction
2. Methods that could increase the abscopal effect
Cryoablation, as an alternative to surgical resection, is used widely to treat localized malignant tumors in the breast, liver, lung, kidney, prostate, and soft tissue. This modality has become even more popular because of the development of imaging-guiding techniques and third generation units [41]. The abscopal immune-regulatory effects of cry oablation have been recognized since the 1970s [1,37], which can affect, or potentially eliminate, metastatic tumors. This effect was referred to as cryo-immunotherapy. However, cryoablation alone may not induce an abscopal effect and might require specific conditions to display its effect [5,29,30]. Despite this, clinical and preclinical data indicate that compared with the weaker immunomodulatory effects observed for other thermal ablation techniques, the immune in teractions of cryoablation were particularly apparent [15]. Therefore, a comprehensive study of the long-term efficacy and abscopal effects of cryoablation in the future would be very valuable. In the present review, we discuss the future development of cryoablation from two aspects: The enhancement of immune responses by cryoablation and the combination of cryoablation with immunotherapies, thereby improving immunosti mulation and limiting immunosuppression.
2.1. Enhancement of cryoimmunity by improving ablative technology Apoptosis and necrosis are the primary mechanisms of tumor cell death and have a significantly different impact on cryoimmunity [29]. In a small area around the probe, cryoablation uses expanding special gases to induce necrotic cell death by inducing an ice ball. Necrotic cell death results in the release of heat shock proteins (HSPs), damage associated molecular patterns (DAMPs, antigens, and intracellular organelles [36]. DAMPs can activate the nuclear factor kappa B (NF-κB) pathway, inducing expression of co-stimulatory CD80/86 molecules on DCs. An tigens presented on major histocompatibility complex molecules on DCs display co-stimulators that stimulate T-cells to promote a systemic im mune response, resulting in the so-called “in-vivo dendritic cell vac cine”. Cryoablation produces a potent immunostimulatory response, as shown by the significantly higher levels of NF-κB, serum interleukin (IL)-1, IL-6, and tumor necrosis factor-α post-ablation [4,7]. However, the sublethal temperatures in the peripheral area of the ice ball induce apoptotic cell death. Apoptotic cell death also results in the release of antigens that are picked up by DCs; however, this does not normally include DAMPs. In the absence of phagocytosed DAMPS, activation of
* Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (D. Du), [email protected] (K. Xu). https://doi.org/10.1016/j.cryobiol.2020.02.010 Received 30 October 2019; Received in revised form 20 February 2020; Accepted 21 February 2020 Available online 22 February 2020 0011-2240/© 2020 Elsevier Inc. All rights reserved.
Please cite this article as: Jibing Chen, Cryobiology, https://doi.org/10.1016/j.cryobiol.2020.02.010
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the NF-κB pathway does occur and CD80/CD86 expression is not induced. In the absence of these co-stimulators, the immune response is suppressed by T cell anergy or clonal deletion. Therefore, the cryotherapy-induced systemic immune response seems to rely on necrotic cell death. Thus, both immunostimulatory and immunosuppressive effects are induced by cryoablation alone. The balance between necrosis and apoptosis, which can vary over time, determines whether stimulation or suppression prevails [31]. Therefore, cryoablative techniques should be improved to increase the area of ne crosis and reduce the area of apoptosis. Recent research has focused on two approaches to effect better control of this procedure. The first method comprises patient-specific computational modeling that predicts the temperature isotherms in the ice ball and allows esti mation of the tissue volume that reaches temperatures below 40 � C. The speed and accuracy of these predictions have been enhanced significantly by improved computational method and imaging inputs into the models. The imaging inputs allow the surgeon to visualize the 3D geometry of the frozen region with contours of 0.5 � C, thereby producing real-time feedback during ablation [27]. The second approach uses molecular adjuvants that increase tissue cryosensitivity at the periphery of the ice ball [32]. The solid phase or crystalline ice are modified using thermophysical adjuvants, including salts, antifreeze proteins, and some amino acids, which cause additional direct cell injury because of the presence of ice crystals. The development of targeted delivery methods that deliver the required dose, but do not induce toxicity to the surrounding normal tissue, remains a major challenge in this approach.
cyclophosphamide was significantly more effective at inducing systemic antitumor immunity, achieving a curative effect in a proportion of the mice that had established metastatic disease that was resistant to tumor rechallenge. Lymphocytes isolated from the cured mice comprised an enhanced population of interferon-gamma producing, tumor-specific T cells. Moreover, this antitumor immunity could be transferred to naive recipients. CD8þ cells cell depletion impaired the adoptive transfer of antitumor immunity significantly. In addition, cyclophosphamide treatment combined with cryoablation correlated with a significant decrease in the ratio of effector to regulatory CD4þ T cells [22]. 2.4. Dendritic cell therapy DCs are antigen presenting cells comprising the first line of defense that can take up, process, and present tumor antigens. Upon activation by infection, the expression of co-stimulators in DCs increases, which then activate a larger lymphocyte response [22]. Imiquimod, a topically-applied toll-like receptor (TLR)7 agonist, stimulates immature DCs to express surface co-stimulators, including CD80 and CD86. Imiquimod-activated DCs go on to trigger Th1 cell immunity. The administration of cryoablation combined with topical Imiquimod resulted in significant protection against rechallenge in 90% of cases, compared with 30% resulting from cryotherapy alone. Cryotherapy and Imiquimod can work together for synergy to treat some kind of tumor [35]. Synthetic CpG-oligodeoxynucleotides (CpG ODNs) have been con structed from bacterial DNA. DCs activated by TLR9 in response to CpGs secrete IFN-α, which induces clumping and migration of more DCs. B cells secrete Th1 inducing mediators, resist programmed cell death, and increase their expression of co-stimulators in response to stimulation by TLRs activated by CpGs. Thus, the innate immune response can be stimulated by the application of artificial CpG ODNs. CpG ODNs administered peritumorally following local destructive therapy increased DC activation and improved the tumor specific CD8þ T cell response. Furthermore, treatment with a combination of CpG ODNs and cryoablation caused existing secondary tumors to regress in 40% of mice and protected them completely against outgrowth of local recurrence at 15 days after treatment [28]. Immature DCs alone injected intratumorally enhanced the prolifer ation of CD8þ T cells. In addition, ex vivo immature DCs combined with cryotherapy administration resulted in significantly prolonged survival after amputation of the foot bearing the primary tumor and after rechallenge [6,16,21]. We have studied the beneficial effects of combining ex vivo DC infusion with cryoablative therapy. In liver, lung, breast, and pancreatic cancer, and the survival of patients who received DCs/CIK (cytokine-induced killers) infusion was longer compared with that induced by cryoablation alone [23,34,42].
2.2. Granulocyte macrophage colony-stimulating factor (GM-CSF) GM-CSF stimulates DCs to display tumor antigens, making GM-CSFs useful for cancer immunotherapy. A combination of cryoablation and GM-CSF could enhance the antitumor effects. A study in a murine sub cutaneous glioma model showed that the combined therapy could syn ergistically improve specific anti-tumor immunity, including increased activation and numbers of DCs. In addition, Th1 cell secretion of inter feron (IFN)-γ in the mouse spleen increased and CD8þT cells’ cytolytic activity produced a significantly increased cytotoxic effect on malignant cells [40]. A pilot clinical study in six patients with renal cell cancer showed that percutaneous cryoablation of lung metastasis in combination with aerosolized GM-CSF could induce systemic cellular and humoral im mune responses. In four of six patients, the authors observed specific in vitro antitumor antibody responses, tumor-specific cytotoxic T lympho cytes, and enhanced production of Th1 cytokines. Importantly, the clinical responses seemed to be associated with the size of the humoral and cellular antitumor responses [38]. However, a clinical study showed that cryoablation plus intralesional GM-CSFs correlated with increased HSP70 levels after therapy; however, no significant induction of anti-tumor T cell responses was detected [17].
2.5. Natural killer cell therapy
2.3. Depletion of regulatory T cells (Tregs)
NK are non-specific killer cells that belong to the innate immune system, playing important roles in the early stages of the fight against cancer [14]. Increased understanding of the functions of NK cells together with progress in NK cell biology, have shown promising anti-tumor effects on various cancers resulting from adoptive NK cell transfer. In contrast to cytotoxic T cells or other immunocytes identified in the target, NK cells are trained to recognize “non-self” histocompat ibility antigens on cell surfaces via killer cell immunoglobulin-like (KIR) receptors. The production of immune-active cytokines by NK cells makes them attractive tools for immunotherapy. Cryoablation combined with allogeneic NK cells produced a synergistic effect, resulting in enhanced immune function and improved quality of life of the patients. Two groups of patients with hepatocellular carcinoma underwent cryo-NK and cryo treatment alone, in which cryo-NK showed a survival benefit [24,25].
A subset of CD4þ T cells, termed regulatory T cells (Tregs), decrease the capacity of a tumor-bearing host to mount an immune response against tumor antigens. Tregs express the transcription factor forkhead box P3 (FOXP3) and CD25, and can potently suppress immunity via the inhibition of natural killer (NK) cells and cytotoxic T lymphocytes. Tregs are also believed to function in tolerance to self-antigens and tumors [17]. Directly targeting CD25þFOXP3þ Tregs for depletion represents a more direct method of overcoming immune regulation. In addition, this inhibitory mechanism can be diminished by the administration of anti-CD25 antibodies [8]. The anti-cancer drug cyclophosphamide depletes Tregs selectively. In a mouse model of metastatic colon cancer, compared with surgical excision or cauterization, cryoablation combined with 2
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Fig. 1. Currently identified cryoablation-associated immunotherapies. The 7 numbers in the figure represent the 7 methods mentioned in the article that can enhance the cryoimmunology, that is, 7 cryo-immunotherapies. Granulocyte-macrophage colony-stimulating factor, GM-CSF; Natural killer cells, NK; Te, effector T cell; CTLA-4, cytotoxic T lymphocyte-associated antigen-4; PD-1, programmed death receptor 1; Treg, regulatory T cell; Cy, low dose cyclophosphamide.
2.6. Immunological checkpoint inhibitors
2.7. Hydrogen gas therapy
Cytotoxic T lymphocyte-associated antigen (CTLA)-4 binds to cos timulatory B7 molecules to inhibit T cell stimulation competitively, which promotes T cell anergy. Anti-CTLA-4 antibodies, such as Ipili mumab and tremelimumab, have achieved some success in relieving this regulatory bottleneck. Similarly, an inhibitory receptor found on T cells, programmed death receptor (PD)-1, is activated by programmed cell death 1 ligand (PD-L1), which inhibits T cell function, thereby inducing apoptosis. Anti-PD-1 drugs, such as Avelumab, Durvalumab, Nivolumab, and Pembrolizumab, have been approved for the treatment of many malignancies. Thus, the ability of tumors to evade the host immune system may be associated with the CTLA-4 and PD-1 pathways, making them prime targets for immunomodulation, especially in combination with ablation. The combination of anti-CTLA-4 therapy with cryoablation signifi cantly increased the number of effector T-cells in the cryoablated tissue. In addition to efficient freezing-induced ablation and reduction of the primary tumor, a second tumor (implanted after-cryoablation) dis played a strong CD8þ T cell response [39]. Two recent clinical studies supported the feasibility of combined cryoablation and anti-CTLA-4 treatments. Eleven patients with hepatocellular carcinoma were treated with the CTLA-4 inhibitor tremelimumab with cryoablation. The results showed that in some patients, CD8þ T-cells accumulated in their tumor tissue, which could enhance the therapeutic effect [18]. In addition, the combination of cryoablation with ipilimumab was assessed for its feasibility in treating breast cancer. The results showed that the combination triggered a systemic immune reaction in the patients [26]. At 1 week after cryoablation, circulating PD-L1 and intratumoral PD-L1 levels had increased significantly, which was associated with poor prognosis after cryoablation [43]. These results suggested cryoablation combined with systemic PD-1 inhibitor therapy would be reasonable. Further studies are necessary to determine the reversal effect of immune cell exhaustion via anti-PD-1 therapy [2].
Hydrogen inhalation has been found to have an adjuvant effect in the clinical treatment of various advanced cancers (e.g. gall bladder cancer [11,13] and nasopharyngeal cancer [9]), especially lung cancer [10,12]. Cytotoxic CD8þT cells become exhausted after continued stimulation by carcinoma cells, thus losing their proliferative, cytokine production, or cytotoxic capabilities. Exhausted CD8þ T cells show dysfunctional mitochondria, resulting from inactivation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and subse quently express immune checkpoint inhibitors, including PD-1 [33]. Recently, hydrogen was demonstrated to stimulate PGC-1α [13,20], leading to enhanced mitochondrial function [19], which might rescue exhausted CD8þ T cells. A prospective study of 55 patients suffering from stage IV colorectal carcinoma indicated that hydrogen treatment for 3 h/day resulted in decreased levels of exhausted terminal PD-1þCD8þ T cells and increased levels of active terminal PD-1-CD8þ T cells. This hydrogen gas treatment-associated effect correlates significantly with enhanced progression-free and overall survival [3]. In 2019, another prospective study of patients (n ¼ 82) with multiple stage III and IV cancers showed a significant benefit after 4 weeks of hydrogen inhalation. Hydrogen treatment for 4 weeks could decrease the levels of tumor markers and control tumor growth; the most obvious effect were on lung cancer, and the effect on patients with stage III disease was better than that on pa tients with stage IV disease [12]. Based on these observations, it is reasonable to propose that the inhalation of hydrogen gas before and after cryoablation could provide improved prognosis by reversing the imbalance toward PD-1þCD8þ T cells. 3. Discussion and conclusion Cryoablation is currently the only method that preserves the immunogenicity of tumor antigens and may cause abscopal effects. For more patients to enjoy the added benefit of this therapy, it is necessary to induce an immune response instead of immune tolerance. Numerous 3
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known immunotherapies might be combined with cryotherapy to constitute cryo-immunotherapy (Fig. 1). The main limitation of this combined therapy might be the choice of therapies based on immune function assessment.
[21] A.M. Krieg, Therapeutic potential of Toll-like receptor 9 activation, Nat. Rev. Drug Discov. 5 (2006) 471–484. [22] M.Y. Levy, A. Sidana, W.H. Chowdhury, S.B. Solomon, C.G. Drake, R. Rodriguez, E. J. Fuchs, Cyclophosphamide unmasks an antimetastatic effect of local tumor cryoablation, J. Pharmacol. Exp. Therapeut. 330 (2009) 596–601. [23] M. Lin, S. Liang, F. Jiang, J. Xu, W. Zhu, W. Qian, Y. Hu, Z. Zhou, J. Chen, L. Niu, K. Xu, Y. Lv, 2003-2013, a valuable study: autologous tumor lysate-pulsed dendritic cell immunotherapy with cytokine-induced killer cells improves survival in stage IV breast cancer, Immunol. Lett. 183 (2017) 37–43. [24] M. Lin, S. Liang, X. Wang, Y. Liang, M. Zhang, J. Chen, L. Niu, K. Xu, Cryoablation combined with allogenic natural killer cell immunotherapy improves the curative effect in patients with advanced hepatocellular cancer, Oncotarget 8 (2017) 81967–81977. [25] M. Lin, S.Z. Liang, X.H. Wang, Y.Q. Liang, M.J. Zhang, L.Z. Niu, J.B. Chen, H.B. Li, K.C. Xu, Clinical efficacy of percutaneous cryoablation combined with allogenic NK cell immunotherapy for advanced non-small cell lung cancer, Immunol. Res. 65 (2017) 880–887. [26] H.L. McArthur, A. Diab, D.B. Page, J. Yuan, S.B. Solomon, V. Sacchini, C. Comstock, J.C. Durack, M. Maybody, J. Sung, A. Ginsberg, P. Wong, A. Barlas, Z. Dong, C. Zhao, B. Blum, S. Patil, D. Neville, E.A. Comen, E.A. Morris, A. Kotin, E. Brogi, Y.H. Wen, M. Morrow, M.E. Lacouture, P. Sharma, J.P. Allison, C. A. Hudis, J.D. Wolchok, L. Norton, A pilot study of preoperative single-dose ipilimumab and/or cryoablation in women with early-stage breast cancer with comprehensive immune profiling, Clin. Canc. Res. 22 (2016) 5729–5737. [27] L. Ratanaprasatporn, N. Sainani, J.B. Duda, A. Aghayev, S. Tatli, S.G. Silverman, P. B. Shyn, Imaging findings during and after percutaneous cryoablation of hepatic tumors, Abdom Radiol (NY) 44 (2019) 2602–2626. [28] P. Redondo, J. del Olmo, A. Lopez-Diaz de Cerio, S. Inoges, M. Marquina, I. Melero, M. Bendandi, Imiquimod enhances the systemic immunity attained by local cryosurgery destruction of melanoma lesions, J. Invest. Dermatol. 127 (2007) 1673–1680. [29] M.S. Sabel, Cryo-immunology: a review of the literature and proposed mechanisms for stimulatory versus suppressive immune responses, Cryobiology 58 (2009) 1–11. [30] M.S. Sabel, A. Arora, G. Su, A.E. Chang, Adoptive immunotherapy of breast cancer with lymph node cells primed by cryoablation of the primary tumor, Cryobiology 53 (2006) 360–366. [31] M.S. Sabel, G. Su, K.A. Griffith, A.E. Chang, Rate of freeze alters the immunologic response after cryoablation of breast cancer, Ann. Surg Oncol. 17 (2010) 1187–1193. [32] A.V. Sarabanda, T.J. Bunch, S.B. Johnson, S. Mahapatra, M.A. Milton, L.R. Leite, G. K. Bruce, D.L. Packer, Efficacy and safety of circumferential pulmonary vein isolation using a novel cryothermal balloon ablation system, J. Am. Coll. Cardiol. 46 (2005) 1902–1912. [33] N.E. Scharping, A.V. Menk, R.S. Moreci, R.D. Whetstone, R.E. Dadey, S.C. Watkins, R.L. Ferris, G.M. Delgoffe, The tumor microenvironment represses T cell mitochondrial biogenesis to drive intratumoral T cell metabolic insufficiency and dysfunction, Immunity 45 (2016) 374–388. [34] L.C. Schmeel, F.C. Schmeel, C. Coch, I.G. Schmidt-Wolf, Cytokine-induced killer (CIK) cells in cancer immunotherapy: report of the international registry on CIK cells (IRCC), J. Canc. Res. Clin. Oncol. 141 (2015) 839–849. [35] K.S. Shaw, G.H. Nguyen, M. Lacouture, L. Deng, Combination of imiquimod with cryotherapy in the treatment of penile intraepithelial neoplasia, JAAD Case Rep 3 (2017) 546–549. [36] R. Slovak, J.M. Ludwig, S.N. Gettinger, R.S. Herbst, H.S. Kim, Immuno-thermal ablations - boosting the anticancer immune response, J Immunother Cancer 5 (2017) 78. [37] S. Tanaka, Immunological aspects of cryosurgery in general surgery, Cryobiology 19 (1982) 247–262. [38] A. Thakur, P. Littrup, E.N. Paul, B. Adam, L.K. Heilbrun, L.G. Lum, Induction of specific cellular and humoral responses against renal cell carcinoma after combination therapy with cryoablation and granulocyte-macrophage colony stimulating factor: a pilot study, J. Immunother. 34 (2011) 457–467. [39] R. Waitz, S.B. Solomon, E.N. Petre, A.E. Trumble, M. Fasso, L. Norton, J.P. Allison, Potent induction of tumor immunity by combining tumor cryoablation with antiCTLA-4 therapy, Cancer Res 72 (2012) 430–439. [40] H. Xu, Q. Wang, C. Lin, Z. Yin, X. He, J. Pan, G. Lu, S. Zhang, Synergism between cryoablation and GM-CSF: enhanced immune function of splenic dendritic cells in mice with glioma, Neuroreport 26 (2015) 346–353. [41] K.C. Xu, N.N. Kopper, L.Z. Niu, Modern Cryosurgery for Cancer, World Sci Pub, 2012. [42] Y. Yuanying, N. Lizhi, M. Feng, W. Xiaohua, Z. Jianying, Y. Fei, J. Feng, H. Lihua, C. Jibing, L. Jialiang, X. Kecheng, Therapeutic outcomes of combining cryotherapy, chemotherapy and DC-CIK immunotherapy in the treatment of metastatic nonsmall cell lung cancer, Cryobiology 67 (2013) 235–240. [43] Z. Zeng, F. Shi, L. Zhou, M.N. Zhang, Y. Chen, X.J. Chang, Y.Y. Lu, W.L. Bai, J. H. Qu, C.P. Wang, H. Wang, M. Lou, F.S. Wang, J.Y. Lv, Y.P. Yang, Upregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma, PloS One 6 (2011), e23621.
Declaration of competing interest None. Acknowledgments Not applicable. References [1] R.J. Ablin, Cryoimmunotherapy, Br. Med. J. 3 (1972) 476. [2] L.C. Adam, J. Raja, J.M. Ludwig, A. Adeniran, S.N. Gettinger, H.S. Kim, Cryotherapy for nodal metastasis in NSCLC with acquired resistance to immunotherapy, J Immunother Cancer 6 (2018) 147. [3] J. Akagi, H. Baba, Hydrogen gas restores exhausted CD8þ T cells in patients with advanced colorectal cancer to improve prognosis, Oncol. Rep. 41 (2019) 301–311. [4] S. Basu, R.J. Binder, R. Suto, K.M. Anderson, P.K. Srivastava, Necrotic but not apoptotic cell death releases heat shock proteins, which deliver a partial maturation signal to dendritic cells and activate the NF-kappa B pathway, Int. Immunol. 12 (2000) 1539–1546. [5] J.G. Baust, A.A. Gage, The molecular basis of cryosurgery, BJU Int. 95 (2005) 1187–1191. [6] B. Behm, P. Di Fazio, P. Michl, D. Neureiter, R. Kemmerling, E.G. Hahn, D. Strobel, T. Gress, D. Schuppan, T.T. Wissniowski, Additive antitumour response to the rabbit VX2 hepatoma by combined radio frequency ablation and toll like receptor 9 stimulation, Gut 65 (2016) 134–143. [7] V. Bottero, S. Withoff, I.M. Verma, NF-kappaB and the regulation of hematopoiesis, Cell Death Differ. 13 (2006) 785–797. [8] S. Brode, A. Cooke, Immune-potentiating effects of the chemotherapeutic drug cyclophosphamide, Crit. Rev. Immunol. 28 (2008) 109–126. [9] J. Chen, X. Kong, F. Mu, T. Lu, D. Du, K. Xu, Hydrogen-oxygen therapy can alleviate radiotherapy-induced hearing loss in patients with nasopharyngeal cancer, Ann. Palliat. Med. 8 (2019) 746–751. [10] J. Chen, F. Mu, T. Lu, D. Du, K. Xu, Brain metastases completely disappear in nonsmall cell lung cancer using hydrogen gas inhalation: a case report, OncoTargets Ther. 12 (2019) 11145–11151. [11] J. Chen, F. Mu, T. Lu, Y. Ma, D. Du, K. Xu, A gallbladder carcinoma patient with pseudo-progressive remission after hydrogen inhalation, OncoTargets Ther. 12 (2019) 8645–8651. [12] J.B. Chen, X.F. Kong, Y.Y. Lv, S.C. Qin, X.J. Sun, F. Mu, T.Y. Lu, K.C. Xu, Real world survey" of hydrogen-controlled cancer: a follow-up report of 82 advanced cancer patients, Med. Gas Res. 9 (2019) 115–121. [13] J.B. Chen, Z.B. Pan, D.M. Du, W. Qian, Y.Y. Ma, F. Mu, K.C. Xu, Hydrogen gas therapy induced shrinkage of metastatic gallbladder cancer: a case report, World J Clin Cases 7 (2019) 2065–2074. [14] M. Cheng, Y. Chen, W. Xiao, R. Sun, Z. Tian, NK cell-based immunotherapy for malignant diseases, Cell. Mol. Immunol. 10 (2013) 230–252. [15] K.F. Chu, D.E. Dupuy, Thermal ablation of tumours: biological mechanisms and advances in therapy, Nat. Rev. Canc. 14 (2014) 199–208. [16] M.H. den Brok, R.P. Sutmuller, S. Nierkens, E.J. Bennink, L.W. Toonen, C. G. Figdor, T.J. Ruers, G.J. Adema, Synergy between in situ cryoablation and TLR9 stimulation results in a highly effective in vivo dendritic cell vaccine, Cancer Res 66 (2006) 7285–7292. [17] E. Domingo-Musibay, J.M. Heun, W.K. Nevala, M. Callstrom, T. Atwell, E. Galanis, L.A. Erickson, S.N. Markovic, Endogenous heat-shock protein induction with or without radiofrequency ablation or cryoablation in patients with stage IV melanoma, Oncol. 22 (2017) 1026–e1093. [18] A.G. Duffy, S.V. Ulahannan, O. Makorova-Rusher, O. Rahma, H. Wedemeyer, D. Pratt, J.L. Davis, M.S. Hughes, T. Heller, M. ElGindi, A. Uppala, F. Korangy, D. E. Kleiner, W.D. Figg, D. Venzon, S.M. Steinberg, A.M. Venkatesan, V. Krishnasamy, N. Abi-Jaoudeh, E. Levy, B.J. Wood, T.F. Greten, Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma, J. Hepatol. 66 (2017) 545–551. [19] C. Handschin, B.M. Spiegelman, Peroxisome proliferator-activated receptor gamma coactivator 1 coactivators, energy homeostasis, and metabolism, Endocr. Rev. 27 (2006) 728–735. [20] N. Kamimura, H. Ichimiya, K. Iuchi, S. Ohta, Molecular hydrogen stimulates the gene expression of transcriptional coactivator PGC-1alpha to enhance fatty acid metabolism, NPJ Aging Mech Dis 2 (2016) 16008.
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