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"Tanaka, Kaoru"
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Irradiation Attenuates Systemic Lupus Erythematosus-Like Morbidity in NZBWF1 Mice: Focusing on CD180-Negative Cells
Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies that can induce systemic inflammation. Ultraviolet-A and X-ray irradiation have been reported to have therapeutic effects in patients with SLE. We previously demonstrated that CD180-negative cells, these are radiosensitive, contribute to the development of SLE-like morbidity in NZBWF1 mice. In this study, the effects of irradiation on SLE-like morbidity manifestations in NZBWF1 mice and on CD180-negative cells were investigated. Whole-body irradiation, excluding the head, attenuated SLE-like morbidity in vivo, as indicated by the prevention of the renal lesion development, inhibition of anti-dsDNA antibody production, reduction of urinary protein levels, and prolongation of the lifespan. Irradiation also reduced the proportion of CD180-negative cells in the spleen. Although other immune cells or molecules may be triggered because of the whole-body irradiation treatment, previous research, and the current results suggest a strong relationship between the radiation-induced decrease in CD180-negative cells and the amelioration of SLE-like morbidities. Clinical trials assessing CD180-negative cells as a therapeutic target for SLE have been hampered by the lack of validated cell markers; nonetheless, the present findings suggest that radiotherapy may be a new therapeutic strategy for managing SLE symptoms.
Journal Article
Mitigation of Iron Irradiation-Induced Genotoxicity and Genomic Instability by Postexposure Dietary Restriction in Mice
Background and Purpose. Postexposure onset of dietary restriction (DR) is expected to provide therapeutic nutritional approaches to reduce health risk from exposure to ionizing radiation (IR) due to such as manned space exploration, radiotherapy, or nuclear accidents as IR could alleviate radiocarcinogenesis in animal models. However, the underlying mechanisms remain largely unknown. This study is aimed at investigating the effect from postexposure onset of DR on genotoxicity and genomic instability (GI) induced by total body irradiation (TBI) in mice. Materials and Methods. Mice were exposed to 2.0 Gy of accelerated iron particles with an initial energy of 500 MeV/nucleon and a linear energy transfer (LET) value of about 200 keV/μm. After TBI, mice were either allowed to free access to a standard laboratory chow or treated under DR (25% cut in diet). Using micronucleus frequency (MNF) in bone marrow erythrocytes, induction of acute genotoxicity and GI in the hematopoietic system was, respectively, determined 1 and 2 months after TBI. Results and Conclusions. TBI alone caused a significant increase in MNF while DR alone did not markedly influence the MNF. DR induced a significant decrease in MNF compared to the treatment by TBI alone. Results demonstrated that postexposure onset of DR could relieve the elevated MNF induced by TBI with high-LET iron particles. These findings indicated that reduction in acute genotoxicity and late GI may be at least a part of the mechanisms underlying decreased radiocarcinogenesis by DR.
Journal Article
Altered Induction of Reactive Oxygen Species by X-rays in Hematopoietic Cells of C57BL/6-Tg (CAG-EGFP) Mice
Previous work pointed to a critical role of excessive production of reactive oxygen species (ROS) in increased radiation hematopoietic death in GFP mice. Meanwhile, enhanced antioxidant capability was not demonstrated in the mouse model of radio-induced adaptive response (RAR) using rescue of radiation hematopoietic death as the endpoint. ROS induction by ex vivo X-irradiation at a dose ranging from 0.1 to 7.5 Gy in the nucleated bone marrow cells was comparatively studied using GFP and wild type (WT) mice. ROS induction was also investigated in the cells collected from mice receiving a priming dose (0.5 Gy) efficient for RAR induction in WT mice. Significantly elevated background and increased induction of ROS in the cells from GFP mice were observed compared to those from WT mice. Markedly lower background and decreased induction of ROS were observed in the cells collected from WT mice but not GFP mice, both receiving the priming dose. GFP overexpression could alter background and induction of ROS by X-irradiation in hematopoietic cells. The results provide a reasonable explanation to the previous study on the fate of cells and mice after X-irradiation and confirm enhanced antioxidant capability in RAR. Investigations involving GFP overexpression should be carefully interpreted.
Journal Article
First-line pembrolizumab ± chemotherapy for recurrent/metastatic head and neck cancer: Japanese subgroup of KEYNOTE-048
BackgroundHere, we report the results of the Japanese subgroup of the phase 3 KEYNOTE-048 study of pembrolizumab alone, pembrolizumab plus platinum and 5-fluorouracil (pembrolizumab–chemotherapy), or cetuximab plus platinum and 5-fluorouracil (EXTREME) in previously untreated recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC).MethodsPrimary end points were overall survival (OS) and progression-free survival (PFS). Efficacy was evaluated in patients with PD-L1 combined positive score (CPS) ≥ 20 and ≥ 1 and the total Japanese subgroup (n = 67).ResultsAt data cutoff (25 February 2019), pembrolizumab led to longer OS versus EXTREME in the PD-L1 CPS ≥ 20 subgroup (median, 28.2 vs. 13.3 months; HR, 0.29 [95% CI 0.09–0.89]) and to similar OS in the total Japanese (23.4 vs. 13.6 months; HR, 0.51 [95% CI 0.25–1.05]) and CPS ≥ 1 subgroups (22.6 vs. 15.8 months; HR, 0.66 [95% CI 0.31–1.41]). Pembrolizumab–chemotherapy led to similar OS versus EXTREME in the PD-L1 CPS ≥ 20 (median, 18.1 vs. 15.8 months; HR, 0.72 [95% CI 0.23–2.19]), CPS ≥ 1 (12.6 vs. 15.8 months; HR, 1.19 [95% CI 0.55–2.58]), and total Japanese subgroups (12.6 vs. 13.3 months; unadjusted HR, 1.10 [95% CI 0.55–2.22]). Median PFS was similar for pembrolizumab and pembrolizumab–chemotherapy versus EXTREME in all subgroups. Grades 3–5 treatment-related adverse events occurred in 5 (22%), 19 (76%), and 17 (89%) patients receiving pembrolizumab, pembrolizumab–chemotherapy, and EXTREME, respectively. One patient receiving pembrolizumab–chemotherapy died because of treatment-related pneumonitis.ConclusionThese results support the use of first-line pembrolizumab and pembrolizumab–chemotherapy for Japanese patients with R/M HNSCC.Clinical trial registry ClinicalTrials.gov, NCT02358031.
Journal Article
N-Glycan fucosylation of epidermal growth factor receptor modulates receptor activity and sensitivity to epidermal growth factor receptor tyrosine kinase inhibitor
The glycosylation of cell surface proteins is important for cancer biology processes such as cellular proliferation or metastasis. α1,6‐Fucosyltransferase (FUT8) transfers a fucose residue to n‐linked oligosaccharides on glycoproteins. Herein, we study the effect of fucosylation on epidermal growth factor receptor (EGFR) activity and sensitivity to an EGFR‐specific tyrosine kinase inhibitor (EGFR‐TKI). The increased fucosylation of EGFR significantly promoted EGF‐mediated cellular growth, and the decreased fucosylation by stable FUT8 knockdown weakened the growth response in HEK293 cells. The overexpression of FUT8 cells were more sensitive than the control cells to the EGFR‐TKI gefitinib, and FUT8 knockdown decreased the sensitivity to gefitinib. Finally, to examine the effects in a human cancer cell line, we constructed stable FUT8 knockdown A549 cells, and found that these cells also decreased EGF‐mediated cellular growth and were less sensitive than the control cells to gefitinib. In conclusion, we demonstrated that the modification of EGFR fucosylation affected EGF‐mediated cellular growth and sensitivity to gefitinib. Our results provide a novel insight into how the glycosylation status of a receptor may affect the sensitivity of the cell to molecular target agents. (Cancer Sci 2008; 99: 1611–1617)
Journal Article
U3-1402 sensitizes HER3-expressing tumors to PD-1 blockade by immune activation
Immunotherapy targeting programmed cell death-1 (PD-1) induces durable antitumor efficacy in many types of cancer. However, such clinical benefit is limited because of the insufficient reinvigoration of antitumor immunity with the drug alone; therefore, rational therapeutic combinations are required to improve its efficacy. In our preclinical study, we evaluated the antitumor effect of U3-1402, a human epidermal growth factor receptor 3-targeting (HER3-targeting) antibody-drug conjugate, and its potential synergism with PD-1 inhibition. Using a syngeneic mouse tumor model that is refractory to anti-PD-1 therapy, we found that treatment with U3-1402 exhibited an obvious antitumor effect via direct lysis of tumor cells. Disruption of tumor cells by U3-1402 enhanced the infiltration of innate and adaptive immune cells. Chemotherapy with exatecan derivative (Dxd, the drug payload of U3-1402) revealed that the enhanced antitumor immunity produced by U3-1402 was associated with the induction of alarmins, including high-mobility group box-1 (HMGB-1), via tumor-specific cytotoxicity. Notably, U3-1402 significantly sensitized the tumor to PD-1 blockade, as a combination of U3-1402 and the PD-1 inhibitor significantly enhanced antitumor immunity. Further, clinical analyses indicated that tumor-specific HER3 expression was frequently observed in patients with PD-1 inhibitor-resistant solid tumors. Overall, U3-1402 is a promising candidate as a partner of immunotherapy for such patients.
Journal Article
Diverse echocardiographic changes in the course of hypoxia due to acute exacerbation of idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF) is a progressive parenchymal disease. Pulmonary hypertension (PH) is a potentially lethal complication in the course of IPF. In almost all cases of IPF-PH there is gradual deterioration, but patients can also decline suddenly due to hypoxia. This case report describes the different echocardiographic changes observed in 2 episodes of hypoxic attack in a 73-year-old man. On admission, the tricuspid regurgitation peak gradient (TRPG) was 21 mmHg and the oxygen saturation rate was 94% (O2: 4 L/min). Five days after admission, the TRPG and oxygen saturation rate deteriorated [TRPG: 85 mmHg, oxygen saturation: 72% (O2; 4 L/min)]. He was diagnosed with IPF-PH due to hypoxic pulmonary vasoconstriction. Oxygen therapy and methylprednisolone pulse therapy (MPT) were administered. Five days after the MPT treatment, the hypoxia and PH improved [TRPG: 21 mmHg, oxygen saturation: 95% (O2: 4 L/min)]. Acute exacerbation of IPF (IPF-AE) occurred 20 days after the MPT, and a second dose of MPT was administered. The TRPG and oxygen saturation rate did not decline [TRPG: 27 mmHg, oxygen saturation: 94% (O2: 4 L/min)]. The patient died 10 days after the second dose of MPT. Divergent echocardiographic findings were observed during the deterioration of IPF-AE in the presence of IPF-PH.
Journal Article
Enhanced Effects of Chronic Restraint-Induced Psychological Stress on Total Body Fe-Irradiation-Induced Hematopoietic Toxicity in Trp53-Heterozygous Mice
Humans are exposed to both psychological stress (PS) and radiation in some scenarios such as manned deep-space missions. It is of great concern to verify possible enhanced deleterious effects from such concurrent exposure. Pioneer studies showed that chronic restraint-induced PS (CRIPS) could attenuate Trp53 functions and increase gamma-ray-induced carcinogenesis in Trp53-heterozygous mice while CRIPS did not significantly modify the effects on X-ray-induced hematopoietic toxicity in Trp53 wild-type mice. As high-linear energy transfer (LET) radiation is the most important component of space radiation in causing biological effects, we further investigated the effects of CRIPS on high-LET iron-particle radiation (Fe)-induced hematopoietic toxicity in Trp53-heterozygous mice. The results showed that CRIPS alone could hardly induce significant alteration in hematological parameters (peripheral hemogram and micronucleated erythrocytes in bone marrow) while concurrent exposure caused elevated genotoxicity measured as micronucleus incidence in erythrocytes. Particularly, exposure to either CRISP or Fe-particle radiation at a low dose (0.1 Gy) did not induce a marked increase in the micronucleus incidence; however, concurrent exposure caused a significantly higher increase in the micronucleus incidence. These findings indicated that CRIPS could enhance the deleterious effects of high-LET radiation, particularly at a low dose, on the hematopoietic toxicity in Trp53-heterozygous mice.
Journal Article