Rosmarinic acid, a natural polyphenol, has a potential pro-oxidant risk via NADH-mediated oxidative DNA damage.

BACKGROUND: Rosmarinic acid (RA) has a wide range of beneficial effects on human health. On the other hand, RA has been reported to induce metal-mediated reactive oxygen species (ROS) generation and DNA damage. However, its mechanism remains unknown. In this study, to clarify the underlying mechanism, we analyzed metal-mediated DNA damage in isolated DNA treated with RA and its analog isorinic acid. RESULTS: RA plus Cu(II), but not Fe(III), significantly increased 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation, an indicator of oxidative DNA damage, in calf thymus DNA. Furthermore, a comparison of the 8-oxodG formation induced by RA and its analog isorinic acid suggested that the catechol groups in RA could be associated with their abilities to form 8-oxodG. Interestingly, the 8-oxodG formation induced by RA and isorinic acid plus Cu(II) was markedly enhanced by the addition of NADH, an endogenous reductant. To elucidate the mechanism of RA plus Cu(II)-induced oxidative DNA damage, we examined DNA damage in 32P-labeled DNA treated with RA in the presence of Cu(II). RA plus Cu(II) caused DNA cleavage, which was enhanced by piperidine treatment, suggesting that RA causes not only DNA strand breakage but also base modification. RA plus Cu(II)-induced DNA damage was inhibited by catalase (H2O2 scavenger), bathocuproine (Cu(I) chelator), and methional (scavenger of a variety of ROS other than •OH) but not by typical •OH scavengers and SOD, indicating the involvement of H2O2, Cu(I), and ROS other than •OH. DNA cleavage site analysis showing RA-induced site-specific DNA damage (frequently at thymine and some cytosine residues) supports the involvement of ROS other than •OH, because •OH causes DNA cleavage without site specificity. Based on these results, Cu(I) and H2O2 generation with concomitant RA autoxidation could lead to the production of Cu(I)-hydroperoxide, which induces oxidative DNA damage. o-Quinone and o-semiquinone radicals are likely to be again reduced to RA by NADH, which dramatically increases oxidative DNA damage, particularly at low concentrations of RA. CONCLUSIONS: In this study, physiologically relevant concentrations of RA effectively induced oxidative DNA damage in isolated DNA through redox cycle reactions with copper and NADH.

Taurine reduces microglia activation in the brain of aged senescence-accelerated mice by increasing the level of TREM2.

Alzheimer's disease (AD), a chronic neurodegenerative disorder, is the leading cause of dementia. Over-activated microglia is related to amyloid-beta (Aß) and phosphorylated tau (phospho-tau) accumulation in the AD brain. Taurine is an amino acid with multiple physiological functions including anti-inflammatory effects, and has been reported to be neuroprotective in AD. However, the role of taurine in microglia-mediated AD remains unclear. Here, we examined the effects of taurine on the brains of senescence-accelerated mouse prone 8 (SAMP8) mice by comparing those administered 1% taurine water with those administered distilled water (DW). We observed increased levels of taurine and taurine transporter (TAUT) in the brains of the taurine-treated mice compared with those of control mice. Immunohistochemical and Western blot analyses revealed that taurine significantly reduced the number of activated microglia, levels of phospho-tau and Aß deposit in the hippocampus and cortex. Triggering receptors expressed on myeloid cells-2 (TREM2) are known to protect against AD pathogenesis. Taurine upregulated TREM2 expression in the hippocampus and cortex. In conclusion, the present study suggests that taurine treatment may upregulate TREM2 to protect against microglia over-activation by decreasing the accumulation of phospho-tau and Aß; providing an insight into a novel preventive strategy in AD.

Oxidative DNA damage: Induction by fructose, in vitro, and its enhancement by hydrogen peroxide.

Sucrose and high-fructose corn syrup comprise nearly equal amounts of glucose and fructose. With the use of high-fructose corn syrup in the food industry, consumption of fructose, which may be a tumor promoter, has increased dramatically. We examined fructose-induced oxidative DNA damage in the presence of Cu(II), with or without the addition of H2O2. With isolated DNA, fructose induced Cu(II)-mediated DNA damage, including formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), to a greater extent than did glucose, and H2O2 enhanced the damage. In cultured human cells, 8-oxodG formation increased significantly following treatment with fructose and the H2O2-generating enzyme glucose oxidase. Fructose may play an important role in oxidative DNA damage, suggesting a possible mechanism for involvement of fructose in carcinogenesis.

Myricetin causes site-specific DNA damage via reactive oxygen species generation by redox interactions with copper ions.

Myricetin (MYR), found in tea and berries, may have preventive effects on diseases, including Alzheimer's disease and cancer. However, MYR is also a mutagen, inducing DNA damage in the presence of metal ions. We have studied the molecular mechanisms of DNA damage by MYR in the presence of Cu(II) (MYR+Cu). Using 32P-5'-end-labeled DNA fragments, we analyzed site-specific DNA damage caused by MYR+Cu. MYR+Cu caused concentration-dependent DNA strand breaks and base alterations, leading to cleavage of DNA at thymine, cytosine, and guanine nucleotides. Formation of the oxidative DNA damage indicator, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), in calf thymus DNA was increased by MYR+Cu. The production of 8-oxodG in MYR-treated HL-60 cells was significantly higher than in HP100 cells, which are more resistant to H2O2 than are HL-60 cells. Reactive oxygen species (ROS) scavengers were used to elucidate the mechanism of DNA damage. DNA damage was not inhibited by typical free hydroxyl radical (•OH) scavengers such as ethanol, mannitol, or sodium formate. However, methional, catalase, and bathocuproine inhibited DNA damage induced by MYR+Cu. These results suggest that H2O2, Cu(I), and ROS other than •OH are involved in MYR+Cu-induced DNA damage. We conclude that the Cu(I)/Cu(II) redox cycle and concomitant H2O2 production via autoxidation of MYR generate a complex of H2O2 and Cu(I), probably Cu(I)-hydroperoxide, which induces oxidative DNA damage.

Knockdown of TFRC suppressed the progression of nasopharyngeal carcinoma by downregulating the PI3K/Akt/mTOR pathway.

BACKGROUND: The transferrin receptor (TfR) encoded by TFRC gene is the main cellular iron importer. TfR is highly expressed in many cancers and is expected to be a promising new target for cancer therapy; however, its role in nasopharyngeal carcinoma (NPC) remains unknown. METHODS: The TfR levels were investigated in NPC tissues and cell lines using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. Knockdown of TFRC using two siRNA to investigate the effects on intracellular iron level and biological functions, including proliferation by CKK-8 assay, colony formation, cell apoptosis and cell cycle by flow cytometry, migration and invasion, and tumor growth in vivo by nude mouse xenografts. RNA sequencing was performed to find possible mechanism after TFRC knockdown on NPC cells and further verified by western blotting. RESULTS: TfR was overexpressed in NPC cell lines and tissues. Knockdown of TFRC inhibited cell proliferation concomitant with increased apoptosis and cell cycle arrest, and it decreased intracellular iron, colony formation, migration, invasion, and epithelial-mesenchymal transition in HK1-EBV cells. Western blotting showed that TFRC knockdown suppressed the levels of the iron storage protein FTH1, anti-apoptotic marker BCL-xL, and epithelial-mesenchymal transition markers. We confirmed in vivo that TFRC knockdown also inhibited NPC tumor growth and decreased Ki67 expression in tumor tissues of nude mouse xenografts. RNA sequencing and western blotting revealed that TFRC silencing inhibited the PI3K/Akt/mTOR signaling pathway. CONCLUSIONS: These results indicated that TfR was overexpressed in NPC, and TFRC knockdown inhibited NPC progression by suppressing the PI3K/Akt/mTOR signaling pathway. Thus, TfR may serve as a novel biomarker and therapeutic target for NPC.

The role of miR-21 as a predictive biomarker and a potential target to improve the effects of chemoradiotherapy against head and neck squamous cell carcinoma.

This study aimed to clarify whether circulating miR-21 represents a predictive biomarker in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy, and to investigate the effect of miR-21 inhibitor for chemoradiation in human SCC cells. Plasma samples were obtained from 22 patients with HNSCC and 25 non-cancer volunteers. Plasma miR-21 expression was measured using real-time quantitative reverse transcription polymerase chain reaction. The effects of miR-21 inhibitor in human SCC cells were investigated by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and western blot analysis. As a result, plasma miR-21 expression was higher in HNSCC patients than in control patients (P < 0.001). Seven patients with recurrence showed significantly higher plasma miR-21 than the 15 patients without recurrence. And high miR-21 expression group showed poor overall survival. Moreover, miR-21 inhibition significantly enhanced cisplatin- or radiation-induced apoptosis. Western blot analysis suggested the programmed cell death 4 protein as a potential target of miR-21 in relation to apoptosis. In conclusion, this study provides new insights into the role of miR-21 as a predictive biomarker for HNSCC treated with chemoradiotherapy and suggests a potential target to improve the effects of chemoradiotherapy against HNSCC.

Overexpression of Insulin Receptor Substrate 1 (IRS1) Relates to Poor Prognosis and Promotes Proliferation, Stemness, Migration, and Oxidative Stress Resistance in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) is one of the oxidative stress-driven carcinogenesis through chronic inflammation. Insulin receptor substrate 1 (IRS1), an adaptor protein of insulin signaling pathways, is associated with the progression of many inflammation-related cancers. This study hypothesized that oxidative stress regulates IRS1 expression and that up-regulation of IRS1 induces CCA progression. The localizations of IRS1 and an oxidative stress marker (8-oxodG) were detected in CCA tissues using immunohistochemistry (IHC). The presence of IRS1 in CCA tissues was confirmed using immortal cholangiocyte cells (MMNK1), a long-term oxidative-stress-induced cell line (ox-MMNK1-L), and five CCA cell lines as cell culture models. IRS1 was overexpressed in tumor cells and this was associated with a shorter patient survival time and an increase in 8-oxodG. IRS1 expression was higher in ox-MMNK1-L cells than in MMNK1 cells. Knockdown of IRS1 by siRNA in two CCA cell lines led to inhibition of proliferation, cell cycle progression, migration, invasion, stemness, and oxidative stress resistance properties. Moreover, a transcriptomics study demonstrated that suppressing IRS1 in the KKU-213B CCA cell line reduced the expression levels of several genes and pathways involved in the cellular functions. The findings indicate that IRS1 is a key molecule in the connection between oxidative stress and CCA progression. Therefore, IRS1 and its related genes can be used as prognostic markers and therapeutic targets for CCA therapy.

Oxidative DNA Damage by N4-hydroxycytidine, a Metabolite of the SARS-CoV-2 Antiviral Molnupiravir.

Molnupiravir is an antiviral agent recently used for treating coronavirus disease 2019 (COVID-19). Here, we demonstrate that N4-hydroxycytidine (NHC), a molnupiravir metabolite, treated with cytidine deaminase (CDA) induced Cu(II)-mediated oxidative DNA damage in isolated DNA. A colorimetric assay revealed hydroxylamine generation from CDA-treated NHC. The site specificity of DNA damage also suggested involvement of hydroxylamine in the damage. Furthermore, Cu(I) and H2O2 play an important role in the DNA damage. We propose oxidative DNA damage via CDA-mediated metabolism as a possible mutagenic mechanism of NHC, highlighting the need for careful risk assessment of molnupiravir use in therapies for viral diseases, including COVID-19.

Taurine induces upregulation of p53 and Beclin1 and has antitumor effect in human nasopharyngeal carcinoma cells in vitro and in vivo.

Taurine is an amino acid that has several physiological functions. Previously, we reported the apoptosis-inducing effect of taurine in human nasopharyngeal carcinoma (NPC) cells in vitro. However, the effect of taurine on NPC cell growth in vivo has not been elucidated. Autophagy plays an important role in cell metabolism and exhibits antitumor effects under certain conditions. In this study, we investigated the effects of taurine on apoptosis- and autophagy-related molecules in NPC cells in vitro and in vivo. In our in vitro study, NPC cells (HK1-EBV) were treated with taurine, and Western blot and immunocytochemical analyses revealed that taurine co-upregulated Beclin 1 and p53, with autophagy upregulation. In the in vivo study, we used a nude mouse model with subcutaneous xenografts of HK1-EBV cells. Once the tumors reached 2-3 mm in diameter, the mice were provided with distilled water (control group) or taurine dissolved in distilled water (taurine-treated group) ad libitum (day 1) and sacrificed on day 13. The volume and weight of the tumors were significantly lower in the taurine-treated group. Using immunohistochemistry (IHC), we confirmed that taurine treatment reduced the distinct cancer nest areas. IHC analyses also revealed that taurine promoted apoptosis, as evidenced by an increase in cleaved caspase-3, accompanied by upregulation of p53. Additionally, taurine increased LC3B and Beclin 1 expression, which are typical autophagy markers. The present study demonstrated taurine-mediated tumor growth suppression. Therefore, taurine may be a novel preventive strategy for NPC.

Targeting fructose metabolism by glucose transporter 5 regulation in human cholangiocarcinoma.

Alterations in cellular metabolism may contribute to tumor proliferation and survival. Upregulation of the facilitative glucose transporter (GLUT) plays a key role in promoting cancer. GLUT5 mediates modulation of fructose utilization, and its overexpression has been associated with poor prognosis in several cancers. However, its metabolic regulation remains poorly understood. Here, we demonstrated elevated GLUT5 expression in human cholangiocarcinoma (CCA), using RNA sequencing data from samples of human tissues and cell lines, as compared to normal liver tissues or a cholangiocyte cell line. Cells exhibiting high-expression of GLUT5 showed increased rates of cell proliferation and ATP production, particularly in a fructose-supplemented medium. In contrast, GLUT5 silencing attenuated cell proliferation, ATP production, cell migration/invasion, and improved epithelial-mesenchymal transition (EMT) balance. Correspondingly, fructose consumption increased tumor growth in a nude mouse xenograft model, and GLUT5 silencing suppressed growth, supporting the tumor-inhibitory effect of GLUT5 downregulation. Furthermore, in the metabolic pathways of fructolysis-Warburg effect, the expression levels of relative downstream genes, including ketohexokinase (KHK), aldolase B (ALDOB), lactate dehydrogenase A (LDHA), and monocarboxylate transporter 4 (MCT4), as well as hypoxia-inducible factor 1 alpha (HIF1A), were altered in a GLUT5 expression-dependent manner. Taken together, these findings indicate that GLUT5 could be a potential target for CCA therapeutic approach via metabolic regulation.

Copper-mediated DNA damage caused by purpurin, a natural anthraquinone.

BACKGROUND: Purpurin (1,2,4-trihydroxy-9,10-anthraquinone), a natural red anthraquinone pigment, has historically been used as a textile dye. However, purpurin induced urinary bladder tumors in rats, and displayed a mutagenic activity in assay using bacteria and mammalian cells. Many carcinogenic dyes are known to induce bladder cancers via DNA adduct formation, but carcinogenic mechanisms of purpurin remain unknown. In this study, to clarify the mechanism underlying carcinogenicity of purpurin, copper-mediated DNA damage induced by purpurin was examined using 32P-labeled DNA fragments of human genes relevant to cancer. Furthermore, we also measured 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an indicator of oxidative DNA damage, in calf thymus DNA. RESULTS: Purpurin plus Cu(II) cleaved 32P-labeled DNA fragments only under piperidine treatment, indicating that purpurin caused base modification, but not breakage of the DNA backbone. In the absence of Cu(II), purpurin did not induce DNA cleavage even with piperidine treatment. Purpurin plus Cu(II) caused piperidine-labile sites predominantly at G and some T residues. Bathocuproine, a Cu(I) chelator, completely prevented the occurrence of piperidine-labile sites, indicating a critical role of Cu(I) in piperidine-labile sites induced by purpurin plus Cu(II). On the other hand, methional, a scavenger of a variety of reactive oxygen species (ROS) and catalase showed limited inhibitory effects on the induction of piperidine-labile sites, suggesting that ROS could not be major mediators of the purpurin-induced DNA damage. Considering reported DNA adduct formation by quinone metabolites of several carcinogenic agents, quinone form of purpurin, which is possibly generated via purpurin autoxidation accompanied by Cu(I)/Cu(II) redox cycle, might lead to DNA adducts and piperidine-labile sites. In addition, we measured contents of 8-oxodG. Purpurin moderately but significantly increased 8-oxodG in calf thymus DNA in the presence of Cu(II). The 8-oxodG formation was inhibited by catalase, methional and bathocuproine, suggesting that Cu(I)-hydroperoxide, which was generated via Cu(I) and H2O2, caused oxidative DNA base damage. CONCLUSIONS: We demonstrated that purpurin induces DNA base damage possibly mediated by Cu(I)/Cu(II) redox cycle both with and without ROS generation, which are likely to play an important role in its carcinogenicity.

Suppression of RNF213, a susceptibility gene for moyamoya disease, inhibits endoplasmic reticulum stress through SEL1L upregulation.

RNF213, a susceptibility gene for moyamoya disease, is associated with stress responses to various stressors. We previously reported that Rnf213 knockout (KO) mitigated endoplasmic reticulum (ER) stress-induced diabetes in the Akita mouse model of diabetes. However, the role of RNF213 in ER stress regulation remains unknown. In the present study, RNF213 knockdown significantly inhibited the upregulation of ER stress markers (CHOP and spliced XBP1) by chemical ER stress-inducers in HeLa cells. Levels of SEL1L, a critical molecule in ER-associated degradation (ERAD), were increased by RNF213 knockdown, and SEL1L knockdown prevented the inhibitory effect of RNF213 suppression on ER stress in HeLa cells, indicating SEL1L involvement in this inhibition of ER stress. SEL1L upregulation was also confirmed in pancreatic islets of Rnf213 KO/Akita mice and in Rnf213 KO mouse embryonic fibroblasts. Additionally, RNF213 suppression increased levels of HRD1, which forms a complex with SEL1L to degrade misfolded protein in cells under ER stress. In conclusion, we demonstrate that RNF213 depletion inhibits ER stress possibly through elevation of the SEL1L-HRD1 complex, thereby promoting ERAD in vitro and in vivo.

Mechanism of reactive oxygen species generation and oxidative DNA damage induced by acrylohydroxamic acid, a putative metabolite of acrylamide.

Acrylamide is formed during the heating of food and is also found in cigarette smoke. It is classified by the International Agency for Research on Cancer as a probable human carcinogen (Group 2A). Glycidamide, an epoxide metabolite of acrylamide, is implicated in the mechanism of acrylamide carcinogenicity. Acrylamide causes oxidative DNA damage in target organs. We sought to clarify the mechanism of acrylamide-induced oxidative DNA damage by investigating site-specific DNA damage and reactive oxygen species (ROS) generation by a putative metabolite of acrylamide, acrylohydroxamic acid (AA). Our results, using 32P-5'-end-labeled DNA fragments, indicated that, although AA alone did not damage DNA, AA treated with amidase induced DNA damage in the presence of Cu(II). DNA cleavage occurred preferentially at T and C, and particularly at T in 5'-TG-3' sequences, and the DNA cleavage pattern was similar to that of hydroxylamine. The DNA damage was inhibited by methional, catalase, and Cu(I)-chelator bathocuproine, suggesting that H2O2 and Cu(I) are involved in the mechanism of DNA damage induced by AA treated with amidase. In addition, amidase-treated AA increased 8-oxo-7,8-dihydro-2'-deoxyguanosine formation in calf thymus DNA, an indicator of oxidative DNA damage, in a dose-dependent manner. In conclusion, hydroxylamine, possibly produced from AA treated with amidase, was autoxidized via the Cu(II)/Cu(I) redox cycle and H2O2 generation, suggesting that oxidative DNA damage induced by ROS plays an important role in acrylamide-related carcinogenesis.

GDF10 inhibits cell proliferation and epithelial-mesenchymal transition in nasopharyngeal carcinoma by the transforming growth factor-ß/Smad and NF-κB pathways.

Growth differentiation factor-10 (GDF10) belongs to a member of the transforming growth factor-ß (TGF-ß) superfamily. Dysfunction of the TGF-ß pathway can lead to carcinoma progression. Previous studies have shown that GDF10 acts as a tumor suppressor gene in some cancers. However, the molecular mechanisms of the association between GDF10 and cell functions in nasopharyngeal carcinoma (NPC) remain unclear. In this study, the expression and methylation levels of GDF10 were studied in human subjects and cell lines. Furthermore, overexpression of GDF10 was used to explore its biological function and potential mechanism in NPC cell lines. GDF10 was downregulated in NPC owing to its aberrant promoter methylation. After treatment with 5-aza-2'-deoxycytidine, the expression of GDF10 in NPC cells was reversed. We also confirmed that the overexpression of GDF10 significantly inhibited cell proliferation and tumor growth both in vitro and in vivo, respectively. Additionally, GDF10 overexpression in NPC cells attenuated migration and invasion and inhibited epithelial-to-mesenchymal transition with a decrease in nuclear Smad2 and NF-κB protein accumulation. GDF10 was silenced owing to its promoter hypermethylation, and it might originally act as a functional tumor suppressor via TGF-ß/Smad and NF-κB signaling pathways in NPC.

MicroRNA expression in lung tissues of asbestos-exposed mice: Upregulation of miR-21 and downregulation of tumor suppressor genes Pdcd4 and Reck.

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 < .05). Especially, miR-21, an oncogenic miRNA, was significantly upregulated by both chrysotile and crocidolite. In database analysis, miR-21 was predicted to target tumor suppressor genes programmed cell death 4 (Pdcd4) and reversion-inducing-cysteine-rich protein with kazal motifs (Reck). Although real-time PCR showed that Pdcd4 was not significantly downregulated by asbestos exposure, Western blotting and immunohistochemistry revealed that PDCD4 expression was reduced especially by chrysotile. Reck was significantly downregulated by chrysotile in real-time PCR and immunohistochemistry. CONCLUSIONS: This is the first study demonstrating that miR-21 was upregulated and corresponding tumor suppressor genes were downregulated in lung tissues of asbestos-exposed animals. These molecular events are considered to be an early response to asbestos exposure and may contribute to pulmonary toxicity and carcinogenesis.

Influence of Epstein-Barr virus and human papillomavirus infection on macrophage migration inhibitory factor and macrophage polarization in nasopharyngeal carcinoma.

BACKGROUND: To assess the effects of Epstein-Barr virus (EBV) and human papillomavirus (HPV) infection on the tumor microenvironment, we examined the relationship between viral infection status, macrophage migration inhibitory factor (MIF), and tumor-associated macrophages in nasopharyngeal carcinoma (NPC). METHODS: A tissue microarray containing 150 cores from 90 patients with NPC and six with chronic inflammation was used. EBV and HPV status were detected using in situ hybridization with commercial EBER1 and HPV16/18 probes. Immunofluorescence double staining of MIF, pan-macrophage marker CD68, M1 macrophage marker CD11c, and M2 macrophage marker CD163 were analyzed using the same tissue microarray. The levels of these markers between NPC and inflammation cases and between tumor nests and stroma were compared. Correlations among these markers were analyzed. RESULTS: We found EBER1(+) cases in 90% of NPC patients, including 10% EBV/HPV co-infection. M1 macrophages mainly infiltrated the tumor nest, while M2 macrophages infiltrated the tumor stroma. We found a significant positive correlation between EBER1 levels and MIF levels in tumor nests and a significant positive correlation between HPV16/18 and CD11c(+) cell levels in NPC tissues. CONCLUSIONS: It is suggested that MIF is associated with EBV, and M1 macrophage infiltration is affected by HPV status in NPC.

Glycyrrhizin Attenuates Carcinogenesis by Inhibiting the Inflammatory Response in a Murine Model of Colorectal Cancer.

Glycyrrhizin (GL), an important active ingredient of licorice root, which weakens the proinflammatory effects of high-mobility group box 1 (HMGB1) by blocking HMGB1 signaling. In this study, we investigated whether GL could suppress inflammation and carcinogenesis in an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced murine model of colorectal cancer. ICR mice were divided into four groups (n = 5, each)-control group, GL group, colon cancer (CC) group, and GL-treated CC (CC + GL) group, and sacrificed after 20 weeks. Plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were measured using an enzyme-linked immunosorbent assay. The colonic tissue samples were immunohistochemically stained with DNA damage markers (8-nitroguanine and 8-oxo-7,8-dihydro-2'-deoxy-guanosine), inflammatory markers (COX-2 and HMGB1), and stem cell markers (YAP1 and SOX9). The average number of colonic tumors and the levels of IL-6 and TNF-α in the CC + GL group were significantly lower than those in the CC group. The levels of all inflammatory and cancer markers were significantly reduced in the CC + GL group. These results suggest that GL inhibits the inflammatory response by binding HMGB1, thereby inhibiting DNA damage and cancer stem cell proliferation and dedifferentiation. In conclusion, GL significantly attenuates the pathogenesis of AOM/DSS-induced colorectal cancer by inhibiting HMGB1-TLR4-NF-κB signaling.

Promoter hypermethylation of early B cell factor 1 (EBF1) is associated with cholangiocarcinoma progression.

DNA hypermethylation in a promoter region causes gene silencing via epigenetic changes. We have previously reported that early B cell factor 1 (EBF1) was down-regulated in cholangiocarcinoma (CCA) tissues and related to tumor progression. Thus, we hypothesized that the DNA hypermethylation of EBF1 promoter would suppress EBF1 expression in CCA and induce its progression. In this study, the DNA methylation status of EBF1 and mRNA expression levels were analyzed in CCA and normal bile duct (NBD) tissues using a publicly available database of genome-wide association data. The results showed that the DNA methylation of EBF1 promoter region was significantly increased in CCA tissues compared with those of NBD. The degree of methylation was negatively correlated with EBF1 mRNA expression levels. Using methylation-specific PCR technique, the DNA methylation rates of EBF1 promoter region were investigated in CCA tissues (n=72). CCA patients with high methylation rates of EBF1 promoter region in the tumor tissues (54/72) had a poor prognosis. Higher methylation rates of EBF1 promoter region have shown in all CCA cell lines than that of an immortal cholangiocyte cell line (MMNK1). Upon treatment with the DNA methyltransferase inhibitor 5-Aza-dC, increased EBF1 expression levels and reduced DNA methylation rates were observed in CCA cells. Moreover, restoration of EBF1 expression in CCA cells led to inhibition of cell growth, migration and invasion. In addition, RNA sequencing analysis suggested that EBF1 is involved in suppression of numerous pathways in cancer. Taken together, DNA hypermethylation in the EBF1 promoter region suppresses EBF1 expression and induces CCA progression with aggressive clinical outcomes.

Subcellular localization of HMGB1 in human cholangiocarcinoma: correlation with tumor stage.

Cholangiocarcinoma (CCA) is a malignant disease with a poor prognosis, and several studies have been conducted using different molecular markers as a tool for CCA diagnosis, including Clonorchis sinensis (CS)-CCA. We initially identified the expression profiles of the three markers of interest, HMGB1, SOX9, and YAP1, using GSE (GSE76297 and GSE32958) datasets. Upregulated levels of these three proteins were detected in CCA samples compared to those in normal samples. To clarify this issue, 24 human CCA tissues with paired adjacent normal tissues were evaluated using immunohistochemical staining. Of the three markers, the total cellular staining intensities were scanned, and subcellular localization was scored in the nuclear and cytoplasmic regions. The intensities of HMGB1, SOX9, and YAP1 were elevated in CCA tissues than the adjacent normal tissues. Individual scoring of subcellular localization revealed that the expression levels of HMGB1 (nucleus) and YAP1 (nucleus and cytoplasm) were significantly different from the pathologic M stage. Moreover, the translocation pattern was categorized using "site-index", and the results demonstrated that the overexpression of HMGB1 and SOX9 was mostly observed in both the nucleus and cytoplasm, whereas YAP1 was predominantly expressed in the cytoplasm of tumor cells. Interestingly, the site index of HMGB1 was moderately correlated with the tumor stage (r = 0.441, p = 0.031). These findings imply that the overexpression of subcellular HMGB1 could be associated with the metastatic status of patients with CS-CCA, which was shown to be effective for CS-CCA prognosis.

Proteomic analysis of the monkey hippocampus for elucidating ischemic resistance.

It is well-known that the cornu Ammonis 1 (CA1) sector of hippocampus is vulnerable for the ischemic insult, whereas the dentate gyrus (DG) is resistant. Here, to elucidate its underlying mechanism, alternations of protein oxidation and expression of DG in the monkey hippocampus after ischemia-reperfusion by the proteomic analysis were studied by comparing CA1 data. Oxidative damage to proteins such as protein carbonylation interrupt the protein function. Carbonyl modification of molecular chaperone, heat shock 70 kDa protein 1 (Hsp70.1) was increased remarkably in CA1, but slightly in DG. In addition, expression levels of nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase sirtuin-2 (SIRT2) was significantly increased in DG after ischemia, but decreased in CA1. Accordingly, it is likely that SIRT2 upregulation and negligible changes of carbonylation of Hsp70.1 exert its neuroprotective effect in DG. On the contrary, carbonylation level of dihydropyrimidinase related protein 2 (DRP-2) and l-lactate dehydrogenase B chain (LDHB) were slightly increased in CA1 as shown previously, but remarkably increased in DG after ischemia. It is considered that DRP-2 and LDHB are specific targets of oxidative stress by ischemia insult and high carbonylation levels of DRP-2 may play an important role in modulating ischemic neuronal death.