研究者詳細 - 豊國　伸哉

Target genes in fenton reaction-induced carcinogenisis: A novel concept 国際誌

Toyokuni, S, Hiroyasu, M, Ozeki, M, Hiai, H

FREE RADICAL BIOLOGY AND MEDICINE 33 巻頁： S177 - S177 2002年

Radiation-induced kidney injury: a role for chronic oxidative stress? 国際誌

Mike E Robbins, Weiling Zhao, Charles S Davis, Shinya Toyokuni, Stephen M Bonsib

Micron (Oxford, England : 1993) 33 巻 ( 2 ) 頁： 133 - 41 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）

Kidney irradiation clearly leads to a progressive reduction in function associated with concomitant glomerulosclerosis and/or tubulointerstitial fibrosis. However, the particular cell types, mediators and/or mechanisms involved in the development and progression of radiation nephropathy remain ill defined. Angiotensin II (Ang II) plays a major pathogenic role; administration of Ang II blockers markedly abrogates the severity of radiation nephropathy in experimental models. Both ionizing radiation and Ang II signal via generation of reactive oxygen species (ROS). Thus, we hypothesized that localized kidney irradiation might lead to a chronic oxidative stress. In view of the difficulty in measuring ROS in vivo we adopted an indirect immunohistochemical approach in which we used a monoclonal antibody specific for 8-hydroxy-2'-deoxyguanosine (8-OHdG), one of the most commonly used markers of DNA oxidation. The right kidney of 7-8 week-old male Sprague-Dawley rats was removed. Five to 6 weeks later the remaining hypertrophied kidney was irradiated with single doses of 0-20.0 Gy X-rays. Groups of rats, three per dose, were killed at 4, 8, 16 and 24 weeks post-irradiation, their kidneys fixed, and sections stained with the 8-OHdG-specific antibody N45.1. For quantitation of glomerular DNA oxidation with the N45.1 antibody stained sections, 50 glomeruli/animal were counted. The presence of any intensely stained nuclei within the glomerular tuft was scored as positive. Quantitation of tubular DNA oxidation employed a 10 x 10 point ocular grid. Sections were examined at 400 magnification; 250 tubular profiles were counted. All tubules with any nuclear staining were scored as positive.Sham-irradiated kidneys showed little evidence of DNA oxidation over the experimental period. In contrast, localized kidney irradiation led to a marked, dose-independent increase in glomerular and tubular cell nuclear DNA oxidation. This increase was evident at the first time point studied, i.e. 4 weeks after irradiation, and persisted for up to 24 weeks postirradiation. DNA oxidation in the irradiated kidney was only seen in apparently viable glomerular and tubular cells. Thus, while from 16 to 24 weeks post-irradiation structural alterations had progressed to glomerular sclerosis and tubular atrophy, positive staining for 8-OHdG was not observed in severely atrophic tubules. Similarly, fewer positive staining cells were noted in glomeruli undergoing sclerosis, while none were seen in totally sclerotic glomeruli. These data support the hypothesis that renal irradiation is associated with a chronic and persistent oxidative stress.

Radiation-induced kidney injury: a role for chronic oxidative stress?

Robbins ME, Zhao W, Davis CS, Toyokuni S, Bonsib SM

Micron (Oxford, England : 1993) 33 巻 ( 2 ) 頁： 133 - 41 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Micron

Kidney irradiation clearly leads to a progressive reduction in function associated with concomitant glomerulosclerosis and/or tubulointerstitial fibrosis. However, the particular cell types, mediators and/or mechanisms involved in the development and progression of radiation nephropathy remain ill defined. Angiotensin II (Ang II) plays a major pathogenic role; administration of Ang II blockers markedly abrogates the severity of radiation nephropathy in experimental models. Both ionizing radiation and Ang II signal via generation of reactive oxygen species (ROS). Thus, we hypothesized that localized kidney irradiation might lead to a chronic oxidative stress. In view of the difficulty in measuring ROS in vivo we adopted an indirect immunohistochemical approach in which we used a monoclonal antibody specific for 8hydroxy-2′-deoxyguanosine (8-OHdG), one of the most commonly used markers of DNA oxidation. The right kidney of 7-8 week-old male Sprague-Dawley rats was removed. Five to 6 weeks later the remaining hypertrophied kidney was irradiated with single doses of 0-20.0 Gy X-rays. Groups of rats, three per dose, were killed at 4, 8, 16 and 24 weeks post-irradiation, their kidneys fixed, and sections stained with the 8-OHdG-specific antibody N45.1. For quantitation of glomerular DNA oxidation with the N45.1 antibody stained sections, 50 glomeruli/animal were counted. The presence of any intensely stained nuclei within the glomerular tuft was scored as positive. Quantitation of tubular DNA oxidation employed a 10 × 10 point ocular grid. Sections were examined at 400 magnification; 250 tubular profiles were counted. All tubules with any nuclear staining were scored as positive. Sham-irradiated kidneys showed little evidence of DNA oxidation over the experimental period. In contrast, localized kidney irradiation led to a marked, dose-independent increase in glomerular and tubular cell nuclear DNA oxidation. This increase was evident at the first time point studied, i.e. 4 weeks after irradiation, and persisted for up to 24 weeks postirradiation. DNA oxidation in the irradiated kidney was only seen in apparently viable glomerular and tubular cells. Thus, while from 16 to 24 weeks post-irradiation structural alterations had progressed to glomerular sclerosis and tubular atrophy, positive staining for 8-OHdG was not observed in severely atrophic tubules. Similarly, fewer positive staining cells were noted in glomeruli undergoing sclerosis, while none were seen in totally sclerotic glomeruli. These data support the hypothesis that renal irradiation is associated with a chronic and persistent oxidative stress. © 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/s0968-4328(01)00006-3

Target genes in Fenton reaction-induced carcinogenesis: A novel concept 国際誌

Toyokuni, S, Hiroyasu, M, Ozeki, M, Hiai, H

XI BIENNIAL MEETING OF THE SOCIETY FOR FREE RADICAL RESEARCH INTERNATIONAL 頁： 459 - 462 2002年

Comparison between high-performance liquid chromatography and enzyme-linked immunosorbent assay for the determination of 8-hydroxy-2′-deoxyguanosine in human urine 査読有り国際誌

Shimoi K., Kasai H., Yokota N., Toyokuni S., Kinae N.

Cancer Epidemiology Biomarkers and Prevention 11 巻 ( 8 ) 頁： 767 - 770 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Cancer Epidemiology Biomarkers and Prevention

8-Hydroxy-2′-deoxyguanosine (8-OH-dG), which has been regarded as a potential marker of oxidative DNA damage induced by reactive oxygen species, was measured in human urine by a commercial ELISA using a monoclonal antibody N45.1 and by high-performance liquid chromatography (HPLC) coupled to an electrochemical detector (HPLCECD) to evaluate whether the ELISA system is applicable to human monitoring studies. The urine samples were collected from 120 healthy men ages 18-58 in a steel-manufacturing company. A good correlation (r = 0.833; P < 0.0001) was observed between the two methods on HPLC-purified 8- OH-dG fractions from 23 urine samples. The mean value (±SD) of 8-OH-dG (μg/g creatinine) was 5.47 (±2.97) by HPLC-ECD assay and 5.50 (±2.36) by ELISA. However, the correlation (r) between the two methods on 120 original urine samples was 0.460 [P < 0.001; mean value (±SD) of 8-OH-dG (μg/g creatinine) was 4.46 (±2.03) by the HPLC assay and 9.33 (±3.23) by ELISA]. ELISA estimates were about 2-fold higher than the HPLC estimates on original urine. For an unknown reason, 10% of the urine samples showed more than a 4-fold increase in value by ELISA. It is suggested that the ELISA system is applicable for comparative human monitoring studies. Prepurification of 'samples is required to determine the absolute value of 8-OH-dG in individual urine samples by ELISA.

Birth of offspring transplantation of cryopreserved immature testicular pieces and in-vitro microinsemination

Shinohara, T, Inoue, K, Ogonuki, N, Kanatsu-Shinohara, M, Miki, H, Nakata, K, Kurome, M, Nagashima, H, Toyokuni, S, Kogishi, K, Honjo, T, Ogura, A

Human Reproduction 17 巻頁： 3039-3045 - 3045 2002年

Amelioration of cisplatin toxicity by a fermented grain food product. 査読有り国際誌

Yukiko Minamiyama, Shigekazu Takemura, Shinya Toyokuni, Yoshihiro Nishino, Keiichi Yamasaki, Seikan Hai, Satoshi Yamamoto, Shigeru Okada

BioFactors (Oxford, England) 16 巻 ( 3-4 ) 頁： 105 - 15 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）

The most noticeable hypothesis regarding the pathogenesis of cisplatin toxicity, seen mainly in kidney and intestine, is oxidative stress, an imbalance between free-radical generating cisplatin and radical scavenging systems. This paper describes the role of the antioxidant system in cisplatin-induced toxicity and the protective effect by a processed grain food (Antioxidant Biofactor: AOB), which has been shown to exhibit strong antioxidant activity. Male Fischer 344 rats were used. They were pre-fed either a basal diet (control, 15 g/day) or the diet supplemented with AOB to provide 6.5% or 20% of total diet throughout the experiment. Cisplatin (5 mg/kg, i.v.) was administered at the start of the experiment, and the animals were sacrificed 5 days later. Blood urea nitrogen (BUN) and plasma creatinine, NO2(-) and NO3(-) (NOx) were determined from the plasma. The levels of 4-hydroxy-2-nonenal (a lipid peroxidation product), 8-hydroxy-deoxyguanosine (8-OHdG, an oxidatively modified DNA adduct) and nitrotyrosine were histologically analyzed. The cisplatin administration resulted in a loss of body weight and elevations of BUN, serum creatinine and NOx levels, whereas AOB supplement reversed these effects. The severe morphological damages induced in the kidney and intestine by the cisplatin administration were markedly improved in the AOB group. The levels of lipid peroxidation, 8-OHdG, and nitrotyrosine all paralleled the morphological damage. The AOB effect was dose dependent. In conclusion, the present study suggests that certain food additives like AOB may be of benefit against the side effects of cisplatin.

Amelioration of cisplatin toxicity by a fermented grain food product.

Minamiyama Y, Takemura S, Toyokuni S, Nishino Y, Yamasaki K, Hai S, Yamamoto S, Okada S

BioFactors (Oxford, England) 16 巻 ( 3-4 ) 頁： 105 - 15 2002年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：BioFactors

The most noticeable hypothesis regarding the pathogenesis of cisplatin toxicity, seen mainly in kidney and intestine, is oxidative stress, an imbalance between free-radical generating cisplatin and radical scavenging systems. This paper describes the role of the antioxidant system in cisplatin-induced toxicity and the protective effect by a processed grain food (Antioxidant Biofactor: AOB®), which has been shown to exhibit strong antioxidant activity. Male Fischer 344 rats were used. They were pre-fed either a basal diet (control, 15 g/day) or the diet supplemented with AOB® to provide 6.5% or 20% of total diet throughout the experiment. Cisplatin (5 mg/kg, i.v.) was administered at the start of the experiment, and the animals were sacrificed 5 days later. Blood urea nitrogen (BUN) and plasma creatinine, NO2- and NO3- (NOx) were determined from the plasma. The levels of 4-hydroxy-2-nonenal (a lipid peroxidation product), 8-hydroxy-deoxyguanosine (8-OHdG, an oxidatively modified DNA adduct) and nitrotyrosine were histologically analyzed. The cisplatin administration resulted in a loss of body weight and elevations of BUN, serum creatinine and NOx levels, whereas AOB supplement reversed these effects. The severe morphological damages induced in the kidney and intestine by the cisplatin administration were markedly improved in the AOB group. The levels of lipid peroxidation, 8-OHdG, and nitrotyrosine all paralleled the morphological damage. The AOB effect was dose dependent. In conclusion, the present study suggests that certain food additives like AOB may be of benefit against the side effects of cisplatin.

DOI： 10.1002/biof.5520160306

酸化ストレス発がんの分子機構とその標的遺伝子

豊國伸哉

環境変異原研究 23 巻 ( 3 ) 頁： 177 - 182 2001年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本環境変異原学会

Oxidative stress has been associated with carcinogenesis. In 1982, our laboratory established an oxys-tress-induced carcinogenesis model of rodent kidney by the use of an iron chelate, ferric nitrilotriacetate. This model is unique in that 1) only carcinoma, not sarcoma, is induced, 2) the induced tumor is of high malignant potential to kill the animal by pulmonary metastasis, peritoneal invasion or rupture of the primary tumor, and, 3) increase in a variety of covalently modified products including 8-oxoguanine, thymine-tyrosine cross-link, 4-hydroxy-2-nonenal and its modified proteins are demonstrated in its early stage. Since in general free radicals are not considered to react with specific target molecules in contrast with immune reaction, we undertook to answer the question whether there is any specific target gene (s) in this carcinogenesis model. By genetically analyzing F_1 hybrid rats, we found two chromosomal areas that showed a high incidence of loss of heterozygosity, which lead to a finding that p15^<INK4B>/p16^<INK4A> tumor suppressor genes are one of the major pathways responsible for this oxystress-induced cancer. Furthermore, by screening 84,000 transcripts by differential display techniques, we found that at least 15 genes associated with stress-response or cellular proliferation are differentially expressed in this model. We believe that not only genetic changes but also epigenetic changes play a role in oxidative stress-induced carcinogenesis.

CiNii Research

酸化ストレス発がんの分子機構とその標的遺伝子

豊國伸哉

環境変異原研究 23 巻 ( 3 ) 頁： 177 - 182 2001年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本環境変異原学会

Activation of lectin-like oxidized low-density lipoprotein receptor-1 induces apoptosis in cultured neonatal rat cardiac myocytes

Iwai-Kanai E., Hasegawa K., Sawamura T., Fujita M., Yanazume T., Toyokuni S., Adachi S., Kihara Y., Sasayama S.

Circulation 104 巻 ( 24 ) 頁： 2948 - 2954 2001年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Circulation

Background - Lectin-like oxidized LDL receptor-1 (LOX-1) was originally identified as a receptor expressed predominantly in endothelial cells. LOX-1 can also be expressed in other cell types, and the activation of the LOX-1 pathway has been implicated in apoptosis. There have been no reports, however, about LOX-1 expression in cardiac myocytes or regulation of myocardial cell apoptosis by LOX-1. Methods and Results - In primary cardiac myocytes from neonatal rats, immunohistochemical analyses using a specific monoclonal antibody against LOX-1 demonstrated that LOX-1 expression was markedly induced by stimulation with norepinephrine and endothelin-1. LOX-1 expression was upregulated in cardiac myocytes as well as in vessel walls of failing rat hearts in vivo. In the presence of a low concentration of oxidized LDL that did not induce apoptosis by itself, artificial overexpression of LOX-1 in cardiac myocytes in culture resulted in apoptosis. LOX-1 overexpression induced activation of p38 mitogen-activated protein kinase (MAPK) and oxidative stress in cardiac myocytes, as demonstrated by an increase in positive immunostaining for 8-hydroxy-2′-deoxyguanosine. Inhibition of p38 MAPK by cotransfection of a dominant-negative form of MKK6 as well as by administration of a specific inhibitor, SB203580 or FR167653, almost completely blocked the induction of apoptosis by LOX-1 activation. Antioxidant catalase also blocked LOX-1-induced apoptosis as well as activation of p38 MAPK. Conclusions - These findings demonstrate that LOX-1 expression in cardiac myocytes is induced by neurohormonal factors activated in heart failure and that LOX-1-dependent apoptosis in these cells requires p38 MAPK, a component of oxidant stress-sensitive signaling pathways.

DOI： 10.1161/hc4901.100381

境界悪性卵巣粘液性腫瘍の再発との細胞学的鑑別が困難であった子宮頸部上皮内腺癌の1例

Activation of lectin-like oxidized low-density lipoprotein receptor-1 induces apoptosis in cultured neonatal rat cardiac myocytes

Iwai-Kanai E, Hasegawa K, Sawamura T, Fujita M, Yanazume T, Toyokuni S, Adachi S, Kihara Y, Sasayama S

CIRCULATION 104 巻 ( 24 ) 頁： 2948 - 2954 2001年12月

Activation of lectin-like oxidized low-density lipoprotein receptor-1 induces apoptosis in cultured neonatal rat cardiac myocytes 査読有り

Iwai-Kanai E, Hasegawa K, Sawamura T, Fujita M, Araki M, Yanazume T, Toyokuni S, Adachi S, Kihara Y, Sasayama S

Circulation 104 巻 ( 24 ) 頁： 2948 - 2954 2001年12月

小椋聖子, 清水恵子, 小林八郎, 豊國伸哉, 桜井幹己

日本臨床細胞学会雑誌 40 巻 ( 6 ) 頁： 636 - 640 2001年11月

境界悪性卵巣粘液性腫瘍の再発との細胞学的鑑別が困難であった子宮頸部上皮内腺癌の1例

小椋聖子, 清水恵子, 小林八郎, 豊國伸哉, 桜井幹己

日本臨床細胞学会雑誌 40 巻 ( 6 ) 頁： 636 - 640 2001年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：特定非営利活動法人日本臨床細胞学会

55歳,1経妊1経産.卵巣粘液性腫瘍の再発との鑑別が困難であった子宮頸部上皮内腺癌の1例を経験した.3年前に右卵巣腫瘍破裂で右付属器摘出術が施行され,右卵巣境界悪性粘液性腫瘍,腸上皮型,Ic期と診断され,外来経過観察中であった.子宮頸部擦過細胞診で異型腺細胞集団が認められ,子宮頸部腺系病変あるいは卵巣粘液性腫瘍の再発が疑われ,単純子宮全摘術と左付属器摘出術を施行した.摘出標本の組織診で子宮頸部上皮内腺癌と診断され,子宮体部,左付属器に悪性所見は認められなかった.婦人科領域の重複癌の診断では,細胞所見のみならず臨床所見や画像診断を加味した総合的判断が必要と思われた