TY - JOUR
T1 - Barriers to radiation-induced in situ tumor vaccination
AU - Wennerberg, Erik
AU - Lhuillier, Claire
AU - Vanpouille-Box, Claire
AU - Pilones, Karsten A.
AU - García-Martínez, Elena
AU - Rudqvist, Nils Petter
AU - Formenti, Silvia C.
AU - Demaria, Sandra
N1 - Funding Information:
SD is supported by grants from NIH (R01 CA201246 and R01 CA198533) and from The Chemotherapy Foundation. SF and SD are supported by a grant from the Breast Cancer Research Foundation and SF is further supported by a grant from DOD BCRP (BC100481/W81XWH-11-1-0530). CV-B is supported by a post-doctoral fellowship from the DOD BCRP (W81XWH-13-1-0012). EW is supported by a post-doctoral fellowship from the DOD BCRP (BC160113). EG-M is supported by a grant from GEICAM.
Publisher Copyright:
© 2017 Wennerberg, Lhuillier, Vanpouille-Box, Pilones, García-Martínez, Rudqvist, Formenti and Demaria.
PY - 2017/3/13
Y1 - 2017/3/13
N2 - The immunostimulatory properties of radiation therapy (RT) have recently generated widespread interest due to preclinical and clinical evidence that tumor-localized RT can sometimes induce antitumor immune responses mediating regression of non-irradiated metastases (abscopal effect). The ability of RT to activate antitumor T cells explains the synergy of RT with immune checkpoint inhibitors, which has been well documented in mouse tumor models and is supported by observations of more frequent abscopal responses in patients refractory to immunotherapy who receive RT during immunotherapy. However, abscopal responses following RT remain relatively rare in the clinic, and antitumor immune responses are not effectively induced by RT against poorly immunogenic mouse tumors. This suggests that in order to improve the pro-immunogenic effects of RT, it is necessary to identify and overcome the barriers that pre-exist and/or are induced by RT in the tumor microenvironment. On the one hand, RT induces an immunogenic death of cancer cells associated with release of powerful danger signals that are essential to recruit and activate dendritic cells (DCs) and initiate antitumor immune responses. On the other hand, RT can promote the generation of immunosuppressive mediators that hinder DCs activation and impair the function of effector T cells. In this review, we discuss current evidence that several inhibitory pathways are induced and modulated in irradiated tumors. In particular, we will focus on factors that regulate and limit radiation-induced immunogenicity and emphasize current research on actionable targets that could increase the effectiveness of radiation-induced in situ tumor vaccination.
AB - The immunostimulatory properties of radiation therapy (RT) have recently generated widespread interest due to preclinical and clinical evidence that tumor-localized RT can sometimes induce antitumor immune responses mediating regression of non-irradiated metastases (abscopal effect). The ability of RT to activate antitumor T cells explains the synergy of RT with immune checkpoint inhibitors, which has been well documented in mouse tumor models and is supported by observations of more frequent abscopal responses in patients refractory to immunotherapy who receive RT during immunotherapy. However, abscopal responses following RT remain relatively rare in the clinic, and antitumor immune responses are not effectively induced by RT against poorly immunogenic mouse tumors. This suggests that in order to improve the pro-immunogenic effects of RT, it is necessary to identify and overcome the barriers that pre-exist and/or are induced by RT in the tumor microenvironment. On the one hand, RT induces an immunogenic death of cancer cells associated with release of powerful danger signals that are essential to recruit and activate dendritic cells (DCs) and initiate antitumor immune responses. On the other hand, RT can promote the generation of immunosuppressive mediators that hinder DCs activation and impair the function of effector T cells. In this review, we discuss current evidence that several inhibitory pathways are induced and modulated in irradiated tumors. In particular, we will focus on factors that regulate and limit radiation-induced immunogenicity and emphasize current research on actionable targets that could increase the effectiveness of radiation-induced in situ tumor vaccination.
KW - Abscopal effect
KW - Adenosine
KW - Hypoxia
KW - Immunotherapy
KW - Macrophages
KW - Radiation therapy
KW - Transforming growth factor-β
KW - Tumor microenvironment
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U2 - 10.3389/fimmu.2017.00229
DO - 10.3389/fimmu.2017.00229
M3 - Review article
C2 - 28348554
AN - SCOPUS:85017268441
SN - 1664-3224
VL - 8
JO - Frontiers in immunology
JF - Frontiers in immunology
IS - MAR
M1 - 229
ER -