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Background/aim The aim of the present study was to investigate whether idarubicin (IDR) induces oxidative DNA damage in the presence of copper (II). Materials and methods DNA damage was evaluated by pBR322 plasmid DNA cleavage. The formation of oxidative stress markers [O2 •- and 8-hydroxy-2'-deoxyguanosine (8-OHdG)] was analysed. Results IDR induced DNA damage and O2 •- and 8-OHdG generation in the presence of copper (II). Conclusion IDR induced oxidative DNA damage in the presence of copper (II). Since it has been reported that the concentration of copper in the serum of cancer patients is higher than that in healthy groups, IDR-induced oxidative DNA damage in the presence of copper (II) may play an important role in anticancer therapeutic strategies.

Indium compounds have been widely used in manufacturing displays of mobile phones, computers and televisions. However, inhalation exposure to indium compounds causes interstitial pneumonia in exposed workers and lung cancer in experimental animals. 8-Nitroguanine (8-nitroG) is a mutagenic DNA lesion formed under inflammatory conditions and may participate in indium-induced carcinogenesis. In this study, we examined 8-nitroG formation in A549 cultured human lung epithelial cells treated with indium compounds, including nanoparticles of indium oxide (In2O3) and indium-tin oxide (ITO), and indium chloride (InCl3). We performed fluorescent immunocytochemistry to examine 8-nitroG formation in indium-exposed A549 cells. All indium compounds significantly increased 8-nitroG formation in A549 cells at 5 ng/ml after 4 h incubation. 8-NitroG formation was largely reduced by 1400 W, methyl-β-cyclodextrin (MBCD) and monodansylcadaverine (MDC), suggesting the involvement of nitric oxide synthase and endocytosis. 8-NitroG formation in A549 cells was also largely suppressed by small interfering RNA (siRNA) for high-mobility group box-1 (HMGB1), receptor for advanced glycation and end products (AGER, RAGE) and Toll-like receptor 9 (TLR9). These results suggest that indium compounds induce inflammation-mediated DNA damage in lung epithelial cells via the HMGB1-RAGE-TLR9 pathway. This mechanism may contribute to indium-induced genotoxicity in the respiratory system.

Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in Southeast Asia, hence, identifying easily detectable biomarkers for NPC screening is essential for better diagnosis and prognosis. Using genome‐wide and targeted analyses based on next‐generation sequencing approaches, we previously showed that gene promoters are hypermethylated in NPC tissues. To confirm whether DNA methylation rates of genes could be used as biomarkers for NPC screening, 79 histologically diagnosed NPC patients and 29 noncancer patients were recruited. A convenient quantitative analysis of DNA methylation using real‐time PCR (qAMP) was carried out, involving pretreatment of tissue DNA, and circulating cell‐free DNA (ccfDNA) from nonhemolytic plasma, with methylation‐sensitive and/or methylation‐dependent restriction enzymes. The qAMP analyses revealed that methylation rates of RERG, ZNF671, ITGA4, and SHISA3 were significantly higher in NPC primary tumor tissues compared to noncancerous tissues, with sufficient diagnostic accuracy of the area under receiver operating characteristic curves (AUC). Interestingly, higher methylation rates of RERG in ccfDNA were statistically significant and yielded a very good AUC; however, those of ZNF671, ITGA4, and SHISA3 were not significant. Furthermore, the combination of methylation rates of RERG and ZNF671 in ccfDNA showed higher diagnostic accuracy than either of them individually. In conclusion, the methylation rates of specific genes in ccfDNA can serve as novel biomarkers for early detection and screening of NPC., The present study identified novel blood‐based noninvasive methylation biomarkers for nasopharyngeal carcinoma screening by a combination of RERG and ZNF671 methylation rates in circulating cell‐free DNA.

The relationship between certain lifestyle habits and schoolchildren’s health has previously been reported on, but the exact pathway of the effects lifestyle habits have on physical/psychosocial health (PPH) has not been investigated nor has the relative influence of different habits on schoolchildren’s health. In this study, schoolchildren were recruited from a primary school in Toyama Prefecture, Japan ( n = 576), and the relevant data were collected in June/July 2017. Path analysis was used to examine the relationships of lifestyle habits and physical fitness with PPH among schoolchildren in grades 1–4 and 5–6. Body weight and total fitness scores were found to be not related to the children’s PPH. The pathway via which lifestyle habits influenced PPH was determined successfully. Among children in grades 1–4, sex ( p < .05), age ( p < .01), and breakfast intake ( p < .05) were related to PPH. Among schoolchildren in grades 5–6, the duration of sleep ( p < .05) was related to PPH. Thus, factors related to schoolchildren’s PPH vary by school grade. The identification of the predictors of the PPH of schoolchildren should inform the design of tailored, grade-specific health promotion interventions in Japanese elementary schools.

Acute myeloid leukemia (AML) is a malignant cancer of the hematopoietic system. Although the effectiveness of arsenic compounds has been recognized and applied clinically, some patients are still found resistant to this chemotherapy. In this study, we investigated that a synthetic thyroid hormone analog (TA), 2-iodo-4-nitro-1-(o-tolyloxy) benzene, had a strong apoptosis effect on U937 cells. U937 cells were treated with TA, and examinted the generation of reactive oxygen species (ROS), dysfunction of mitochondria, expression of pro-apoptosis and anti-apoptosis, and cleavage of caspase-3 and Poly (ADP-ribose) polymerase (PARP). Further, it is also evaluated that insight molecular mechanism and signaling pathways involved in the study. It is found that TA significantly induced apoptosis in U937 cells through production of ROS, dysfunction of mitochondria, and activation of caspase cascade. It was also observed that MAPK signaling pathway including ERK, JNK, and P38 signals are involved in the induction of apoptosis. Moreover, marked activation of autophagy and ER stress markers such as LC3, P62, Beclin1 and GRP78, CHOP were observed, respectively. Pretreatment with ER stress inhibitor tauroursodeoxycholic acid (TUDCA) and autophagy inhibitor 3-Methyladenine (3-MA) have successfully attenuated and aggravated TA-induced apoptosis, respectively. We further confirmed the active involvement of ER stress and autophagy signals. In conclusion, TA induced apoptosis through ER stress and activation of autophagy, and the latter is not conducive to TA-induced cell death. Our results may provide a new insight into the strategic development of novel therapy for the treatment of AML.

Objectives Asbestos causes lung cancer and malignant mesothelioma in humans, but the precise mechanism has not been well understood. MicroRNA (miRNA) is a short non‐coding RNA that suppresses gene expression and participates in human diseases including cancer. In this study, we examined the expression levels of miRNA and potential target genes in lung tissues of asbestos‐exposed mice by microarray analysis. Methods We intratracheally administered asbestos (chrysotile and crocidolite, 0.05 or 0.2 mg/instillation) to 6‐week‐old ICR male mice four times weekly. We extracted total RNA from lung tissues and performed microarray analysis for miRNA and gene expression. We also carried out real‐time polymerase chain reaction (PCR), Western blotting, and immunohistochemistry to confirm the results of microarray analysis. Results Microarray analysis revealed that the expression levels of 14 miRNAs were significantly changed by chrysotile and/or crocidolite (>2‐fold, P

Background Many studies have already reported on the relationship between exercise habits and health among schoolchildren. However, few have examined social and/or family factors as determinants of exercise habits. Methods This study’s participants included 1721 schoolchildren aged between 6 and 13 who were involved in the Super Shokuiku School Project in January 2016. A survey was conducted to assess gender, grade level, physical activity, lifestyle, overall health, enrichment of school life, social background, and parental lifestyles. Both dislike and lack of physical activity were used to measure poor exercise habits; correlates were analyzed using logistic regression. Results “Lack of close friends” had the strongest links with both dislike (adjusted odds ratio [OR] 5.30; 95% confidence interval [CI], 2.78–10.1) and lack of (adjusted OR 5.40; 95% CI, 2.81–10.4) physical activity. Further, children who engaged in long periods of screen time and lacked parental communication also tended to dislike and lack physical activity. Children with mothers who were unemployed (housewives) and had unhealthy lifestyles, as well as those with poor health, were also more likely to lack physical activity. Conclusion Social and family factors (e.g., having close friends) may be determinants of exercise habits among schoolchildren, independent of their own lifestyle factors. Although a longitudinal study is needed to determine causality, substantial attention may thus be required to these factors when promoting physical activity in children.

Naphthalene is a carcinogenic polycyclic aromatic hydrocarbon, to which humans are exposed as an air pollutant. Naphthalene is metabolized in humans to reactive intermediates such as 1,2-hydroxynaphthalene (1,2-NQH2), 1,4-NQH2, 1,2-naphthoquinone (1,2-NQ), and 1,4-NQ. We examined oxidative DNA damage by these naphthalene metabolites using 32P-labeled DNA fragments from human cancer-relevant genes. 1,2-NQH2 and 1,4-NQH2 induced DNA damage in the presence of Cu(II). The DNA-damaging activity of 1,2-NQH2 was significantly increased in the presence of the reduced form of nicotinamide adenine dinucleotide (NADH), whereas that of 1,4-NQH2 was not. In the presence of NADH, 1,2-NQ induced Cu(II)-dependent DNA damage, whereas 1,4-NQ did not. The calculated energy of the lowest unoccupied molecular orbital (LUMO), which corresponds to the reduction potential, was estimated to be −0.67 eV for 1,2-NQ and −0.75 eV for 1,4-NQ. These results suggest that 1,2-NQ was reduced more easily than 1,4-NQ. Furthermore, 1,2-NQH2, 1,4-NQH2, and 1,2-NQ plus NADH formed 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) as an oxidative DNA marker. Catalase and bathocuproine inhibited DNA damage, suggesting that H2O2 and Cu(I) were involved. These results indicate that NQH2s are oxidized to the corresponding NQs via semiquinone radicals, and that H2O2 and Cu(I) are generated during oxidation. 1,2-NQ is reduced by NADH to form the redox cycle, resulting in enhanced DNA damage. The formation of the corresponding semiquinone radicals was supported by an electron paramagnetic resonance (EPR) study. In conclusion, the redox cycle of 1,2-NQ/1,2-NQH2 may play a more important role in the carcinogenicity of naphthalene than that of 1,4-NQ/1,4-NQH2.

To elucidate the molecular mechanisms underlying the progression of head and neck squamous cell carcinoma (HNSCC), we investigated the function of let-7c as a tumor suppressor. Let-7c expression was significantly down-regulated in HNSCC tumor tissues and cell lines. In vitro and in vivo studies revealed that let-7c negatively regulated HNSCC proliferation, migration and epithelial-mesenchymal transition (EMT). To explore the underlying mechanisms that affect these molecular events achieved by let-7c, we predicted its target genes. We performed luciferase assay and confirmed that insulin-like growth factor 1 receptor (IGF1R) and high mobility group AT-hook 2 (HMGA2) were the direct targets of let-7c. Knocking down of IGF1R and HMGA2 inhibited HNSCC progression, including proliferation, migration and EMT in HNSCC cells. Re-expression of these genes overcame let-7c-mediated inhibition. Taken together, our finding suggests that let-7c inhibits HNSCC progression by targeting IGF1R and HMGA2 and might be a novel target for HNSCC treatment.

In Japan, the prevalence of low birth weight (< 2,500 g) has been increasing, probably owing to leanness, exposure to toxic chemicals and smoking. Epidemiological studies revealed that low birth weight poses risks of hypertension, coronary heart diseases and diabetes. Although the precise mechanism has not been understood, there is an urgent need for appropriate public health interventions. MicroRNA (miRNA) is a small RNA consisting of approximately 22 nucleotides and distributed in a wide variety of organs and body fluids. miRNAs are involved in the pathogenesis of various human diseases and expected to be their potential biomarkers. The interest on the study on miRNA in the research field of developmental origins of health and disease (DOHaD) has been growing, and the number of related papers has been increasing. There are several molecular epidemiological studies on the relationship between maternal miRNA and fetal development. The effects of smoking and dietary factors on miRNA expression and fetal development have been investigated in epidemiological and experimental studies. However, the role of maternal miRNA in fetal development has not been well understood so far. In this review, the current status of studies on miRNA expression in DOHaD research is described and future perspectives are discussed.

Carbon black (CB) is a nanomaterial used mainly in rubber products. Exposure to CB by inhalation causes malignant lung tumors in experimental animals. CB inhalation may cause chronic inflammation in the respiratory system, leading to carcinogenesis, but the mechanism remains unclear. Reactive oxygen and nitrogen species are generated from inflammatory and epithelial cells under inflammatory conditions, and resulting DNA damage may contribute to carcinogenesis. In this study, we performed immunocytochemistry to determine whether CB exposure induces formation of 8-nitroguanine (8-nitroG), a nitrative DNA lesion formed under inflammatory conditions, in RAW 264.7 macrophage and A549 lung epithelial cells. We compared the DNA-damaging effects of CB particles with primary diameter 56nm (CB56) and 95nm (CB95). Both types of CB induced 8-nitroG formation, mainly in the nucleus of RAW 264.7 and A549 cells, and CB95 tended to induce more 8-nitroG formation than did CB56. Flow cytometry revealed that CB95 generated larger amount of reactive oxygen species than did CB56 in RAW 264.7 cells. The Griess method showed that CB95 produced significantly larger amount of nitric oxide (NO) than did CB56. Flow cytometry showed that CB95 was more efficiently internalized into the cells than was CB56. The cellular uptake of CB and 8-nitroG formation in RAW 264.7 cells were reduced by monodansylcadaverine, an inhibitor of clathrin-mediated endocytosis, and by siRNA for Ctlc (clathrin heavy chain) gene. CB induces nitrative DNA damage in cultured cells, and clathrin-mediated endocytosis is involved, at least in part.

Background Many studies have already reported on the relationship between exercise habits and health among schoolchildren. However, few have examined social and/or family factors as determinants of exercise habits. This study investigated factors related to both dislike and lack of physical activity among schoolchildren. Methods This study’s participants included 1,984 school children (1,001 boys and 983 girls) aged between 6 and 13 from the Super Shokuiku School Project in January 2016. A survey was conducted to assess sex, grade level, physical activity, lifestyle, overall health, enrichment of school life, social background, and parental lifestyles. Both the dislike and lack of physical activity were defined as poor exercise habits; correlates were analyzed using a logistic regression. Results “Lack of close friends” had the strongest links with both dislike (adjusted odds ratio [OR] 5.30; 95% confidence interval [CI], 2.78-10.1) and lack of (adjusted OR 5.40; 95%CI, 2.81-10.4) physical activity. Further, children who engaged in long periods of screen time and lacked parental communication also tended to dislike and lack physical activity. Children with mothers who were unemployed (housewife) and had undesirable lifestyles as well as those with poor health were also more likely to lack physical activity. Conclusion Social and family factors (e.g., close friends) may be determinants of exercise habits among schoolchildren independently of their own lifestyle factors. Although a longitudinal study is needed to determine causality, substantial attention should thus be paid to these factors when promoting physical activity.

Taurine displays anti-tumor activity in some kinds of human cancers. However, the underlying mechanisms are poorly understood. Epstein-Barr virus-related nasopharyngeal carcinoma (NPC) is a distinctive type of head and neck cancer in Southeast Asia with the highest incidence in South China. We examined an apoptosis-inducing effect of taurine against NPC cells (HK1 and HK1-EBV) to clarify the mechanisms of anti-tumor effects of taurine by immunocytochemical methods. We observed that taurine induced cleavage of caspase-9/3 in a concentration-dependent manner, suggesting the involvement of mitochondrial apoptotic signals. Both PTEN and p53 activation were detected in a dose-dependent manner after taurine treatment in NPC cells. In conclusion, taurine may play an anti-tumor role by activating tumor suppressor PTEN and p53.

Background/aim This study aimed to investigate aclarubicin (ACR)-induced oxidative DNA damage and apoptosis. Materials and methods ACR-induced apoptosis was analyzed using HL-60 leukemia cells and HP100 cells, hydrogen peroxide (H2O2)-resistant cells derived from HL-60 cells. ACR-induced DNA damage was analyzed using plasmid DNA. Results HL-60 cells were more sensitive to ACR than HP100 cells. In HP100 cells, DNA ladder formation and caspase-3/7 activity induced by ACR were suppressed or delayed in comparison to those in HL-60 cells. ACR-induced DNA damage occurred in the presence of Cu(II), and scavenger experiments showed that the reactive species causing DNA damage appeared to be generated from H2O2 and Cu(I). Moreover, we detected intracellular Cu(I) induced by ACR in HL-60 cells, using CopperGREEN™, a fluorescent probe for detection of Cu(I) ion specifically. Conclusion ACR-induced DNA damage and apoptosis can be accounted for by the involvement of H2O2 and Cu(I).

Taurine displays anti-tumor activity in some kinds of human cancers. However, the underlying mechanisms are poorly understood. Epstein-Barr virus-related nasopharyngeal carcinoma (NPC) is a distinctive type of head and neck cancer in Southeast Asia with the highest incidence in South China. We examined an apoptosis-inducing effect of taurine against NPC cells (HK1 and HK1-EBV) to clarify the mechanisms of anti-tumor effects of taurine by immunocytochemical methods. We observed that taurine induced cleavage of caspase-9/3 in a concentration-dependent manner, suggesting the involvement of mitochondrial apoptotic signals. Both PTEN and p53 activation were detected in a dose-dependent manner after taurine treatment in NPC cells. In conclusion, taurine may play an anti-tumor role by activating tumor suppressor PTEN and p53.

Morin is a potential inhibitor of amyloid β-peptide aggregation. This aggregation is involved in the pathogenesis of Alzheimer's disease. Meanwhile, morin has been found to be mutagenic and exhibits peroxidation of membrane lipids concurrent with DNA strand breaks in the presence of metal ions. To clarify a molecular mechanism of morin-induced DNA damage, we examined the DNA damage and its site specificity on 32P-5'-end-labeled human DNA fragments treated with morin plus Cu(II). The formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an indicator of oxidative DNA damage, was also determined in calf thymus DNA treated with morin plus Cu(II). Morin-induced DNA strand breaks and base modification in the presence of Cu(II) were dose dependent. Morin plus Cu(II) caused piperidine-labile lesions preferentially at thymine and guanine residues. The DNA damage was inhibited by methional, catalase and Cu(I)-chelator bathocuproine. The typical •OH scavengers ethanol, mannitol and sodium formate showed no inhibitory effect on DNA damage induced by morin plus Cu(II). When superoxide dismutase was added to the solution, DNA damage was not inhibited. In addition, morin plus Cu(II) increased 8-oxodG formation in calf thymus DNA fragments. We conclude that morin undergoes autoxidation in the presence of Cu(II) via a Cu(I)/Cu(II) redox cycle and H2O2 generation to produce Cu(I)-hydroperoxide, which causes oxidative DNA damage.

Various CD44 isoforms are expressed in several cancer stem cells during tumor progression and metastasis. In particular, CD44 variant 9 (CD44v9) is highly expressed in chronic inflammation-induced cancer. We investigated the expression of CD44v9 and assessed whether CD44v9 is a selective biomarker of human cholangiocarcinoma (CCA). The expression profile of CD44v9 was evaluated in human liver flukeOpisthorchis viverrini-related CCA (OV-CCA) tissues, human CCA (independent of OV infection, non-OV-CCA) tissues, and normal liver tissues. CD44v9 overexpression was detected by immunohistochemistry (IHC) in CCA tissues. There was a higher level of CD44v9 expression and IHC score in OV-CCA tissues than in non-OV-CCA tissues, and there was no CD44v9 staining in the bile duct cells of normal liver tissues. In addition, we observed significantly higher expression of inflammation-related markers, such as S100P and COX-2, in OV-CCA tissues compared to that in non-OV and normal liver tissues. Thus, these findings suggest that CD44v9 may be a novel candidate CCA stem cell marker and may be related to inflammation-associated cancer development.

Nasopharyngeal carcinoma (NPC) is a distinctive type of head and neck malignancy with a high incidence in southern China. Previous studies have confirmed that taurine shows an anti-cancer effect on a variety of human tumors by inhibiting cell proliferation and inducing apoptosis. However, the underlying molecular mechanism of its anti-cancer effect on NPC is not well understood. To clarify these anti-cancer mechanisms, we performed cell viability and colony formation assays. Apoptotic cells were quantified by flow cytometry. The expression levels of apoptosis-related proteins were evaluated by Western blot. The results showed that taurine markedly inhibited cell proliferation in NPC cells, but only slightly in an immortalized normal nasopharyngeal cell line. Taurine suppressed colony formation and induced apoptosis of NPC cell lines in a dose-dependent manner. Furthermore, taurine increased the active form of caspase-9/3 in a dose-dependent manner. Taurine down-regulated the anti-apoptotic protein Bcl-xL and up-regulated the pro-apoptotic protein Bax and GRP78, a major endoplasmic reticulum (ER) chaperone. These results suggest the involvement of mitochondrial and ER stress signaling in apoptosis. In addition, taurine increased the levels of PTEN (phosphatase and tensin homolog deleted on chromosome 10) and p53, and reduced phosphorylated Akt (protein kinase B). In conclusion, taurine may inhibit cell proliferation and induce apoptosis in NPC through PTEN activation with concomitant Akt inactivation.

Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder and is characterized by loss of dopaminergic neurons. Biomarkers for tracking disease progression are useful indicators of the pathological conditions or the effects of therapeutic interventions on disease progression, but there are currently no known biomarkers in the blood that correlate with the progression of PD. Several studies have suggested that exosomes reflect intracellular changes that occur in response to pathological conditions and are an effective source of biomarkers for disease progression. To identify candidate biomarkers of disease progression in PD, we isolated exosomes from plasma of PD patients at Hoehn and Yahr (HY) stages II and III and performed protein profiling of the exosomes using two-dimensional differential gel electrophoresis (2D-DIGE). The expression levels of three proteins (clusterin, complement C1r subcomponent, and apolipoprotein A1) in PD patients at HY stages II and III were significantly decreased compared to healthy subjects (p 0.05). Apolipoprotein A1 in PD patients at HY stage III was significantly decreased compared to HY stage II and correlated with progression of PD (r -0.77, p 0.01). Fibrinogen gamma chain in plasma was also decreased in PD patients at HY stages II and III compared to healthy subjects. Therefore, these three exosomal proteins (clusterin, complement C1r subcomponent, and apolipoprotein A1) and fibrinogen gamma chain in plasma may be biomarker candidates for the diagnosis of PD. In particular, the expression levels of apolipoprotein A1 in exosomes may be useful for tracking the progression of PD.

BACKGROUND/AIM One mechanism of the anticancer action of anthracyclines is believed to be oxidative DNA damage. Previously, we reported that doxorubicin induced oxidative DNA damage in the presence of Cu(II). However, the mechanism of pirarubicin-induced oxidative DNA damage has not been well clarified. MATERIALS AND METHODS DNA damage by pirarubicin in the presence of Cu(II) was analyzed using pBR322 plasmid DNA. O2•- derived from pirarubicin in the presence of Cu(II) was detected by cytochrome c reduction. RESULTS Pirarubicin induced DNA damage in the presence of Cu(II). Scavenger experiments suggest that reactive species are generated from H2O2 and Cu(I). Pirarubicin induced O2•- production in the presence of Cu(II). CONCLUSION These findings suggest that pirarubicin plus Cu(II) induces oxidative DNA damage in a similar manner to doxorubicin, and Cu(II)-mediated oxidative DNA damage may serve as a common mechanism for antitumor effects of anthracyclines.

// Shumin Wang 1, 2 , Yingxi Mo 1, 2 , Kaoru Midorikawa 1 , Zhe Zhang 2 , Guangwu Huang 2 , Ning Ma 3 , Weilin Zhao 1, 2 , Yusuke Hiraku 1 , Shinji Oikawa 1 , Mariko Murata 1 1 Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Tsu, Mie, Japan 2 Department of Otolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China 3 Faculty of Nursing Science, Suzuka University of Medical Science, Suzuka, Mie, Japan Correspondence to: Mariko Murata, e-mail: mmurata@doc.medic.mie-u.ac.jp Keywords: nasopharyngeal carcinoma, microRNA, Epstein-Barr virus, tumor suppressor, biomarker Received: July 03, 2015 Accepted: October 02, 2015 Published: October 14, 2015 ABSTRACT Nasopharyngeal carcinoma (NPC) is a malignancy with poor prognosis that is endemic to Southeast Asia. We profiled microRNAs (miRNAs) of NPCs using microarrays and confirmed the results by quantitative RT-PCR. The results revealed that seven miRNAs were significantly up-regulated, and six miRNAs were down-regulated, in NPC tissues relative to noncancerous nasopharyngeal epithelia (NNE). Expression of miR-497 was also significantly reduced in the plasma of NPC patients relative to the plasma of noncancerous control patients. The concordant down-regulation of miR-497 in tissues and plasma suggested that miR-497 could be used as a diagnostic biomarker for NPC. Functional analyses of the effect of miR-497 on cancer phenotypes revealed that transfection of miR-497 mimic into NPC cells suppressed cell growth and migration and induced apoptosis. Subcutaneous xenografts of transfected cells in nude mice demonstrated that miR-497 significantly inhibited tumor growth. Two potential targets of miR-497, ANLN (anillin, actin-binding protein) and HSPA4L (heat shock 70 kDa protein 4–like), both of which were overexpressed in NPC tissues, were negatively regulated by miR-497 mimic in NPC cell lines. Silencing of ANLN and HSPA4L suppressed cell proliferation and migration and induced apoptosis in NPC cells. Our findings indicate that miR-497 is a potent tumor suppressor that inhibits cancer phenotypes by targeting ANLN and HSPA4L in NPC.

Circulating microRNAs (miRNAs) are emerging as promising non-invasive biomarkers for human cancer. Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignancy worldwide, but its overall survival has remained unchanged in the past 3 decades. Biomarkers for evaluating efficacy of cancer therapy are urgently needed. To explore circulating miRNAs as cancer therapy biomarkers, we initially identified that 8 miRNAs were distinctly dysregulated in cancerous tissues compared with adjacent non-cancerous counterparts from 16 patients, using microarray and real-time PCR. Based on this discovery, the comparison study was performed between pre- and 6 months post-operative paired plasma samples on 9 patients. MiR-99a, which was down-regulated in cancerous tissues, was significantly increased in plasma after operation. Meanwhile, oncomiR miR-21 and miR-223 that were up-regulated in cancerous tissues, were significantly reduced in post-operative plasma samples. We firstly report the significant changes of miR-99a in plasma of HNSCC patients after surgery. Furthermore, plasma miR-223 was inversely increased in a patient whose cancer relapsed within 6 months after operation. We conclude that these circulating miRNAs may serve as biomarkers to evaluate the efficacy of therapy and the prognosis of HNSCC.

Reactive oxygen and nitrogen species have been implicated in diverse pathophysiological conditions, including inflammation, neurodegenerative diseases and cancer. Accumulating evidence indicates that oxidative damage to biomolecules including lipids, proteins and DNA, contributes to these diseases. Previous studies suggest roles of lipid peroxidation and oxysterols in the development of neurodegenerative diseases and inflammation-related cancer. Our recent studies identifying and characterizing carbonylated proteins reveal oxidative damage to heat shock proteins in neurodegenerative disease models and inflammation-related cancer, suggesting dysfunction in their antioxidative properties. In neurodegenerative diseases, DNA damage may not only play a role in the induction of apoptosis, but also may inhibit cellular division via telomere shortening. Immunohistochemical analyses showed co-localization of oxidative/nitrative DNA lesions and stemness markers in the cells of inflammation-related cancers. Here, we review oxidative stress and its significant roles in neurodegenerative diseases and cancer.

Background/aim Pirarubicin (THP) has shown equal or superior cytotoxicity compared to doxorubicin. One of the main anticancer actions of doxorubicin is believed to be involved in ROS (reactive oxygen species) generation. Therefore, the anticancer mechanisms of THP may involve ROS generation. The aim of this study was to clarify the mechanisms of THP-induced apoptosis through ROS generation. Materials and methods We analyzed the apoptotic events induced by THP in HL-60 cells and HP100 cells, hydrogen peroxide (H2O2)-resistant cells derived from HL-60. Results The apparent cytotoxicity could be detected at above 0.1 μM in HL-60 cells after 24-h incubation, whereas it was suppressed under these conditions in HP100 cells. In HP100 cells, THP-induced apoptosis, evaluated by DNA ladder formation, H2O2 generation, mitochondrial membrane potential decrease and caspase-3/7 activity, was suppressed or delayed compared to those of HL-60 cells. Conclusion These findings can be explained by the involvement of H2O2 generation in the THP apoptotic pathway. This is the first report on THP-induced apoptosis through the H2O2 generation.

To elucidate the molecular mechanisms underlying the progression of head and neck squamous cell carcinoma (HNSCC), we investigated the function of let-7c as a tumor suppressor. Let-7c expression was significantly down-regulated in HNSCC tumor tissues and cell lines. In vitro and in vivo studies revealed that let-7c negatively regulated HNSCC proliferation, migration and epithelial–mesenchymal transition (EMT). To explore the underlying mechanisms that affect these molecular events achieved by let-7c, we predicted its target genes. We performed luciferase assay and confirmed that insulin-like growth factor 1 receptor (IGF1R) and high mobility group AT-hook 2 (HMGA2) were the direct targets of let-7c. Knocking down of IGF1R and HMGA2 inhibited HNSCC progression, including proliferation, migration and EMT in HNSCC cells. Re-expression of these genes overcame let-7c–mediated inhibition. Taken together, our finding suggests that let-7c inhibits HNSCC progression by targeting IGF1R and HMGA2 and might be a novel target for HNSCC treatment.

Background Epigenetic changes, including DNA methylation, disrupt normal cell function, thus contributing to multiple steps of carcinogenesis. Nasopharyngeal carcinoma (NPC) is endemic in southern China and is highly associated with Epstein-Barr virus (EBV) infection. Significant changes of the host cell methylome are observed in EBV-associated NPC with cancer development. Epigenetic marks for NPC diagnosis are urgently needed. In order to explore DNA methylation marks, we investigated DNA methylation of candidate genes in EBV-associated nasopharyngeal carcinoma. Methods We first employed methyl-capture sequencing and cDNA microarrays to compare the genome-wide methylation profiles of seven NPC tissues and five non-cancer nasopharyngeal epithelium (NNE) tissues. We found 150 hypermethylated CpG islands spanning promoter regions and down-regulated genes. Furthermore, we quantified the methylation rates of seven candidate genes using bisulfite amplicon sequencing for nine NPC and nine NNE tissues. Results All seven candidate genes showed significantly higher methylation rates in NPC than in NNE tissues, and the ratios (NPC/NNE) were in descending order as follows: ITGA4 > RERG > ZNF671 > SHISA3 > ZNF549 > CR2 > RRAD. In particular, methylation levels of ITGA4, RERG, and ZNF671 could distinguish NPC patients from NNE subjects. Conclusions We identified the DNA methylation rates of previously unidentified NPC candidate genes. The combination of genome-wide and targeted methylation profiling by next-generation sequencers should provide useful information regarding cancer-specific aberrant methylation. Electronic supplementary material The online version of this article (doi:10.1186/s12885-017-3482-3) contains supplementary material, which is available to authorized users.

Asbestos causes lung cancer and malignant mesothelioma, and chronic inflammation is considered to participate in carcinogenesis. However, biomarkers to evaluate its carcinogenic risk have not been established. Reactive oxygen/nitrogen species are generated in biological systems under inflammatory conditions and may contribute to carcinogenesis by causing DNA damage. In this study, we examined the relationship between the formation of 8-nitroguanine (8-nitroG), a mutagenic DNA lesion formed during inflammation, and asbestos contents in human lung tissues.We obtained non-tumor lung tissues from patients with (n=15) and without mesothelioma (n=21). The expression of 8-nitroG and related molecules was examined by immunohistochemistry, and their staining intensities were semiquantitatively evaluated. Asbestos contents in lung tissues were analyzed by analytical transmission electron microscopy.In subjects without mesothelioma, staining intensities of 8-nitroG and apurinic/apyrimidinic endonuclease 1 (APE1) were significantly correlated with total asbestos and amphibole contents (p0.05), but not with chrysotile content. In mesothelioma patients, their staining intensities were not correlated with asbestos contents. The double immunofluorescence technique revealed that APE1 was expressed in 8-nitroG-positive cells, suggesting that abasic sites were formed possibly due to the removal of 8-nitroG. The staining intensities of 8-oxo-7,8-dihydro-2'-deoxyguanosine, an oxidative DNA lesion, and its repair enzyme 8-oxoguanine DNA-glycosylase were correlated with age (p0.05), but not with asbestos contents in subjects without mesothelioma.This is the first study to demonstrate that 8-nitroG formation is associated with asbestos contents in human lung tissues. This finding raises a possibility that 8-nitroG serves as a biomarker that can be used to evaluate asbestos exposure and carcinogenic risk.

Infection and chronic inflammation have been recognized as important factors for carcinogenesis. Under inflammatory conditions, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from inflammatory and epithelial cells, and result in the formation of oxidative and nitrative DNA lesions, such as 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-nitroguanine. The DNA damage can cause mutations and has been implicated in inflammation-mediated carcinogenesis. It has been estimated that various infectious agents are carcinogenic to humans (IARC group 1), including bacterium Helicobacter pylori (H. pylori), viruses [hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV) and Epstein-Barr virus (EBV)] and parasites [Schistosoma haematobium (SH) and Opisthorchis viverrini (OV)]. H. pylori, HBV/HCV, HPV, EBV, SH and OV are important risk factors for gastric cancer, hepatocellular carcinoma, nasopharyngeal carcinoma, bladder cancer, and cholangiocarcinoma, respectively. We demonstrated that 8-nitroguanine was strongly formed via inducible nitric oxide synthase (iNOS) expression at these cancer sites of patients. Moreover, 8-nitroguanine was formed in Oct3/4-positive stem cells in SH-associated bladder cancer tissues, and in Oct3/4- and CD133-positive stem cells in OV-associated cholangiocarcinoma tissues. Therefore, it is considered that nitrative and oxidative DNA damage in stem cells may play a key role in infection-related carcinogenesis via chronic inflammation.

Nitrative and oxidative DNA damage plays an important role in inflammation-related carcinogenesis. Chronic inflammation such as parasite infection and primary sclerosing cholangitis can be an etiological factor of cholangiocarcinoma. Using a proteomic approach and double-fluorescent staining, we identified high expression and colocalization of albumin and cytokeratin-19 in liver fluke-associated cholangiocarcinoma tissues, compared with normal livers from cholangiocarcinoma patients and cadaveric donors, respectively. Albumin was detected not only in cells of hyperplastic bile ducts and cholangiocarcinoma, but also in liver stem/progenitor cell origin, such as canal of Hering, ductules, and ductular reactions, suggesting the involvement of stem/progenitor cells in cholangiocarcinoma development. To clarify the involvement of liver stem/progenitor cells in cholangiocarcinoma, we examined several stem/progenitor cell markers (CD133, CD44, OV6, and Oct3/4) in cholangiocarcinoma tissues analyzed by immunohistochemical staining, and measured 8-oxodG levels by using HPLC-ECD as an inflammation-related DNA lesion. In addition, a stem/progenitor cell factor Bmi1, 8-nitroguanine (formed during nitrative DNA damage), DNA damage response (DDR) proteins (phosphorylated ATM and γ-H2AX), and manganese-SOD (Mn-SOD) were analyzed by immunohistochemistry. Stem/progenitor cell markers (CD133, OV6, CD44, and Oct3/4) were positively stained in 56, 38, 47, and 56% of 34 cholangiocarcinoma cases, respectively. Quantitative analysis of 8-oxodG revealed significantly increased levels in CD133- and/or Oct3/4-positive tumor tissues compared to negative tumor tissues, as well as 8-nitroguanine formation detected by immunohistochemistry. In the cases of CD44- and/or OV6-positive tissue, no significant difference was observed. Cholangiocarcinoma patients with CD133- and/or Oct3/4-positive tumor tissues showed significantly lower expression of Mn-SOD and higher DDR protein, γ-H2AX. Moreover, CD133- and/or Oct3/4-positive cholangiocarcinoma patients had significant associations with tumor histology types, tumor stage, and poor prognoses. Our results suggest that CD133 and Oct3/4 in cholangiocarcinoma are associated with increased formation of DNA lesions and the DDR protein, which may be involved in genetic instability and lead to cholangiocarcinoma development with aggressive clinical features.

Opisthorchis viverrini infection induces inflammation-mediated oxidative stress and liver injury, which may alter α-tocopherol and lipid metabolism. We investigated plasma α-tocopherol and lipid profiles in hamsters infected with O. viverrini. Levels of α-tocopherol, cholesterol, and low-density lipoprotein increased in the acute phase of infection. In the chronic phase, α-tocopherol decreased, while triglyceride and very low-density lipoprotein increased. Notably, high-density lipoprotein decreased both in the acute and chronic phases. In the liver, cholesteryl oleate, triolein, and oleic acid decreased in the acute phase, and increased in the chronic phase. Such chronological changes were negatively correlated with the plasma α-tocopherol level. The expression of α-tocopherol-related molecules, ATP-binding cassette transporter A1 (ABCA1) and α-tocopherol transfer protein, increased throughout the experiment. These results suggest that O. viverrini infection profoundly affects on lipid and α-tocopherol metabolism in due course of infection.

Proteomic analysis was performed to search for the diagnostic biomarkers of the early stage of cholangiocarcinoma (CCA). For this purpose, CCA was experimentally induced in hamsters by the combination of N-nitrosodimethylamine (NDMA) treatment and Opisthorchis viverrini (OV) infection. Pooled plasma of normal control, NDMA-treated, OV-infected and OV+NDMA (ON) treated group was separated by 1-D PAGE, and the trypsin-digested bands were analyzed with LC-MS/MS. Among 82 overexpressed proteins, the study focused on 26 proteins overexpressed in ON group because CCA development was almost exclusively found in this group. A further selection was made based on the protein overexpression on day 21, the precancerous stage. Orosomucoid 2 (Orm2) was overexpressed in OV and ON groups and kinesin 18A (KIF18A) was overexpressed in the ON group. The overexpression levels were verified by real-time RT-PCR and western blotting in the liver and plasma. The transcription and translation levels of these two candidate molecules increased significantly at 21 days post-treatment before tumor development. Immunohistochemistry revealed KIF18A was expressed in the epithelial cells of newly formed small bile ducts, some inflammatory cells and hepatocytes. These results suggest that Orm2 and KIF18A could be the potential biomarkers for early diagnosis of CCA.

Barrett’s esophagus (BE) caused by gastroesophageal reflux is a major risk factor of Barrett’s esophageal adenocarcinoma (BEA), an inflammation-related cancer. Chronic inflammation and following tissue damage may activate progenitor cells under reactive oxygen/nitrogen species-rich environment. We previously reported the formation of oxidative/nitrative stress-mediated mutagenic DNA lesions, 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-nitroguanine, in columnar epithelial cells of BE tissues and cancer cells of BEA tissues. We investigated the mechanisms of BEA development in relation to oxidative/nitrative DNA damage and stem cell hypothesis. We examined 8-nitroguanine and 8-oxodG formation and the expression of stem cell marker (CD133) in biopsy specimens of patients with BE and BEA by immunohistochemical analysis in comparison with those of normal subjects. CD133 was detected at apical surface of columnar epithelial cells of BE and BEA tissues, and the cytoplasm and cell membrane of cancer cells in BEA tissues. DNA lesions and CD133 were colocalized in columnar epithelial cells and cancer cells. Their relative staining intensities in these tissues were significantly higher than those in normal subjects. Our results suggest that BE columnar epithelial cells with CD133 expression in apical surface undergo inflammation-mediated DNA damage, and mutated cells acquire the property of cancer stem cells with cytoplasmic CD133 expression.

Titanium dioxide (TiO2) particles are used for surface coating and in a variety of products such as inks, fibers, food, and cosmetics. The present study investigated possible respiratory and cardiovascular effects of TiO2 particles in workers exposed to this particle at high concentration in a factory in China. The diameter of particles collected on filters was measured by scanning electron microscopy. Real-time size-dependent particle number concentration was monitored in the nostrils of four workers using condensation particle counter and optical particle counter. Electrocardiogram was recorded using Holter monitors for the same four workers to record heart rate variability. Sixteen workers underwent assessment of the respiratory and cardiovascular systems. Mass-based individual exposure levels were also measured with personal cascade impactors. The primary particle diameter ranged from 46 to 562 nm. Analysis of covariance of the pooled data of the four workers showed that number of particles with a diameter

Nasopharyngeal carcinoma (NPC) is endemic in southern China. In a genome-wide screen for genes inactivated by promoter hypermethylation, we identified Ras-related associated with diabetes (RRAD). Expression of RRAD was down-regulated in 83.3% (30/36) of the biopsies from NPC patients. RRAD was aberrantly methylated in 74.3% (26/35) of primary tumors, but not in normal nasopharyngeal epithelium. Ectopic RRAD expression in NPC cell lines inhibited the cell growth, colony formation, and cell migration. These results indicate that RRAD might act as a functional tumor suppressor and its epigenetic inactivation may play an important role in NPC development.

Barrett's esophagus (BE), an inflammatory disease, is a risk factor for Barrett's esophageal adenocarcinoma (BEA). Treatment of BE patients with proton pump inhibitors (PPIs) is expected to reduce the risk of BEA. We performed an immunohistochemical study to examine the formation of nitrative and oxidative DNA lesions, 8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxygaunosine (8-oxodG), in normal esophageal, BE with pre- and post-treatment by PPIs and BEA tissues. We also observed the expression of an oxidant-generating enzyme (iNOS) and its transcription factor NF-κB, an antioxidant enzyme (Mn-SOD), its transcription factor (Nrf2) and an Nrf2 inhibitor (Keap1). The immunoreactivity of DNA lesions was significantly higher in the order of BEA>BE>normal tissues. iNOS expression was significantly higher in the order of BEA>BE>normal tissues, while Mn-SOD expression was significantly lower in the order of BEA

Carbonylation is an irreversible and irreparable protein modification induced by oxidative stress. Cholangiocarcinoma (CCA) is associated with chronic inflammation caused by liver fluke infection. To investigate the relationship between protein carbonylation and CCA progression, carbonylated proteins were detected by 2D OxyBlot and identified by MALDI-TOF/TOF analyses in pooled CCA tissues in comparison to adjacent nontumor tissues and normal liver tissues. We identified 14 highly carbonylated proteins in CCA tissues. Immunoprecipitation and Western blot analyses of individual samples confirmed significantly greater carbonylation of serotransferrin, heat shock protein 70-kDa protein 1 (HSP70.1), and α1-antitrypsin (A1AT) in tumor tissues compared to normal tissues. The oxidative modification of these proteins was significantly associated with poor prognoses as determined by the Kaplan-Meier method. LC-MALDI-TOF/TOF mass spectrometry identified R50, K327, and P357 as carbonylated sites in serotransferrin, HSP70.1, and A1AT, respectively. Moreover, iron accumulation was significantly higher in CCA tissues with, compared to those without, carbonylated serotransferrin. We conclude that carbonylated serotransferrin-associated iron accumulation may induce oxidative stress via the Fenton reaction, and the carbonylation of HSP70.1 with antioxidative property and A1AT with protease inhibitory capacity may cause them to become dysfunctional, leading to CCA progression.

Carbon nanotube (CNT) has a promising usage in the field of material science for industrial purposes because of its unique physicochemical property. However, intraperitoneal administration of CNT was reported to cause mesothelioma in experimental animals. Chronic inflammation may contribute to carcinogenesis induced by fibrous materials. 8-Nitroguanine is a mutagenic DNA lesion formed during inflammation and may play a role in CNT-induced carcinogenesis. In this study, we examined 8-nitroguanine formation in A549 human lung alveolar epithelial cells treated with multi-walled CNT (MWCNT) by fluorescent immunocytochemistry. Both MWCNTs with diameter of 20-30 nm (CNT20) and 40-70 nm (CNT40) significantly induced 8-nitroguanine formation at 5 and 10 μg/ml (p