start-ver=1.4 cd-journal=joma no-vol=115 cd-vols= no-issue=10 article-no= start-page=3231 end-page=3247 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240809 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Overcoming immunotherapy resistance and inducing abscopal effects with boron neutron immunotherapy (B-NIT) en-subtitle= kn-subtitle= en-abstract= kn-abstract=Immune checkpoint inhibitors (ICIs) are effective against many advanced malignancies. However, many patients are nonresponders to immunotherapy, and overcoming this resistance to treatment is important. Boron neutron capture therapy (BNCT) is a local chemoradiation therapy with the combination of boron drugs that accumulate selectively in cancer and the neutron irradiation of the cancer site. Here, we report the first boron neutron immunotherapy (B-NIT), combining BNCT and ICI immunotherapy, which was performed on a radioresistant and immunotherapy-resistant advanced-stage B16F10 melanoma mouse model. The BNCT group showed localized tumor suppression, but the anti-PD-1 antibody immunotherapy group did not show tumor suppression. Only the B-NIT group showed strong tumor growth inhibition at both BNCT-treated and shielded distant sites. Intratumoral CD8+ T-cell infiltration and serum high mobility group box 1 (HMGB1) levels were higher in the B-NIT group. Analysis of CD8(+) T cells in tumor-infiltrating lymphocytes (TILs) showed that CD62L- CD44(+) effector memory T cells and CD69(+) early-activated T cells were predominantly increased in the B-NIT group. Administration of CD8-depleting mAb to the B-NIT group completely suppressed the augmented therapeutic effects. This indicated that B-NIT has a potent immune-induced abscopal effect, directly destroying tumors with BNCT, inducing antigen-spreading effects, and protecting normal tissue. B-NIT, immunotherapy combined with BNCT, is the first treatment to overcome immunotherapy resistance in malignant melanoma. In the future, as its therapeutic efficacy is demonstrated not only in melanoma but also in other immunotherapy-resistant malignancies, B-NIT can become a new treatment candidate for advanced-stage cancers. en-copyright= kn-copyright= en-aut-name=FujimotoTakuya en-aut-sei=Fujimoto en-aut-mei=Takuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamasakiOsamu en-aut-sei=Yamasaki en-aut-mei=Osamu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KanehiraNoriyuki en-aut-sei=Kanehira en-aut-mei=Noriyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MatsushitaHirokazu en-aut-sei=Matsushita en-aut-mei=Hirokazu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SakuraiYoshinori en-aut-sei=Sakurai en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KenmotsuNaoya en-aut-sei=Kenmotsu en-aut-mei=Naoya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MizutaRyo en-aut-sei=Mizuta en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=KondoNatsuko en-aut-sei=Kondo en-aut-mei=Natsuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TakataTakushi en-aut-sei=Takata en-aut-mei=Takushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KitamatsuMizuki en-aut-sei=Kitamatsu en-aut-mei=Mizuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=IgawaKazuyo en-aut-sei=Igawa en-aut-mei=Kazuyo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=FujimuraAtsushi en-aut-sei=Fujimura en-aut-mei=Atsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=OtaniYoshihiro en-aut-sei=Otani en-aut-mei=Yoshihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=ShirakawaMakoto en-aut-sei=Shirakawa en-aut-mei=Makoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=ShigeyasuKunitoshi en-aut-sei=Shigeyasu en-aut-mei=Kunitoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=TeraishiFuminori en-aut-sei=Teraishi en-aut-mei=Fuminori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=TogashiYosuke en-aut-sei=Togashi en-aut-mei=Yosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=SuzukiMinoru en-aut-sei=Suzuki en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=FujiwaraToshiyoshi en-aut-sei=Fujiwara en-aut-mei=Toshiyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=MichiueHiroyuki en-aut-sei=Michiue en-aut-mei=Hiroyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= affil-num=1 en-affil=Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=2 en-affil=Department of Dermatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=3 en-affil=Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=4 en-affil=Division of Translational Oncoimmunology, Aichi Cancer Center Research Institute kn-affil= affil-num=5 en-affil=Institute for Integrated Radiation and Nuclear Science, Kyoto University kn-affil= affil-num=6 en-affil=Department of Tumor Microenvironment, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=7 en-affil=Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=8 en-affil=Institute for Integrated Radiation and Nuclear Science, Kyoto University kn-affil= affil-num=9 en-affil=Institute for Integrated Radiation and Nuclear Science, Kyoto University kn-affil= affil-num=10 en-affil=Faculty of Science and Engineering, Kindai University kn-affil= affil-num=11 en-affil=Neutron Therapy Research Center, Okayama University kn-affil= affil-num=12 en-affil=Neutron Therapy Research Center, Okayama University kn-affil= affil-num=13 en-affil=Department of Neurological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=14 en-affil=Neutron Therapy Research Center, Okayama University kn-affil= affil-num=15 en-affil=Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=16 en-affil=Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=17 en-affil=Department of Tumor Microenvironment, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=18 en-affil=Institute for Integrated Radiation and Nuclear Science, Kyoto University kn-affil= affil-num=19 en-affil=Department of Gastroenterological Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences kn-affil= affil-num=20 en-affil=Neutron Therapy Research Center, Okayama University kn-affil= en-keyword=abscopal effect kn-keyword=abscopal effect en-keyword=advanced melanoma kn-keyword=advanced melanoma en-keyword=boron neutron capture therapy kn-keyword=boron neutron capture therapy en-keyword=boron-neutron immunotherapy kn-keyword=boron-neutron immunotherapy en-keyword=immune combination therapy kn-keyword=immune combination therapy END