Details of a Researcher - Soga, Tomoyoshi

Papers - Soga, Tomoyoshi

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Thymidine Catabolism as a Metabolic Strategy for Cancer Survival

Tabata, S., Yamamoto, M., Goto, H., Hirayama, A., Ohishi, M., Kuramoto, T., Mitsuhashi, A., Ikeda, R., Haraguchi, M., Kawahara, K., Shinsato, Y., Minami, K., Saijo, A., Hanibuchi, M., Nishioka, Y., Sone, S., Esumi, H., Tomita, M., Soga, T., Furukawa, T., Akiyama, S.

Cell Rep. 19 ( 7 ) 1313 - 1321 2017.05

Research paper (scientific journal), Joint Work, Accepted

Thymidine phosphorylase (TP), a rate-limiting enzyme in thymidine catabolism, plays a pivotal role in tumor progression; however, the mechanisms underlying this role are not fully understood. Here, we found that TP-mediated thymidine catabolism could supply the carbon source in the glycolytic pathway and thus contribute to cell survival under conditions of nutrient deprivation. In TP-expressing cells, thymidine was converted to metabolites, including glucose 6-phosphate, lactate, 5-phospho-α-D-ribose 1-diphosphate, and serine, via the glycolytic pathway both in vitro and in vivo. These thymidine-derived metabolites were required for the survival of cells under low-glucose conditions. Furthermore, activation of thymidine catabolism was observed in human gastric cancer. These findings demonstrate that thymidine can serve as a glycolytic pathway substrate in human cancer cells.

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Modelling urea-cycle disorder citrullinemia type 1 with disease-specific iPSCs

Yoshitoshi-Uebayashi, E.Y., Toyoda, T., Yasuda, K., Kotaka, M., Nomoto, K., Okita, K., Yasuchika, K., Okamoto, S., Takubo, N., Nishikubo, T., Soga, T., Uemoto, S., Osafune, K.

Biochem Biophys Res Commun. 486 ( 3 ) 613 - 619 2017.05

Research paper (scientific journal), Joint Work, Accepted

Citrullinemia type 1 (CTLN1) is a urea cycle disorder (UCD) caused by mutations of the ASS1 gene, which is responsible for production of the enzyme argininosuccinate synthetase (ASS), and classically presented as life-threatening hyperammonemia in newborns. Therapeutic options are limited, and neurological sequelae may persist. To understand the pathophysiology and find novel treatments, induced pluripotent stem cells (iPSCs) were generated from a CTLN1 patient and differentiated into hepatocyte-like cells (HLCs). CTLN1-HLCs have lower ureagenesis, recapitulating part of the patient's phenotype. l-arginine, an amino acid clinically used for UCD treatment, improved this phenotype in vitro. Metabolome analysis revealed an increase in tricarboxylic acid (TCA) cycle metabolites in CTLN1, suggesting a connection between CTLN1 and the TCA cycle. This CTLN1-iPSC model improves the understanding of CTLN1 pathophysiology and can be used to pursue new therapeutic approaches.

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Cell competition with normal epithelial cells promotes apical extrusion of transformed cells through metabolic changes

Kon, S., Ishibashi, K., Katoh, H., Kitamoto, S., Shirai, T., Tanaka, S., Kajita, M., Ishikawa, S., Yamauchi, H., Yako, Y., Kamasaki, T., Matsumoto, T., Watanabe, H., Egami, R., Sasaki, A., Nishikawa, A., Kameda, I., Maruyama, T., Narumi, R., Morita, T., Sasaki, Y., Enoki, R., Honma, S., Imamura, H., Oshima, M., Soga, T., Miyazaki, J., Duchen, MR.., Nam, J., Onodera, Y., Yoshioka, S., Kikuta, J., Ishii, M., Imajo, M., Nishida, E., Fujioka, Y., Ohba, Y., Sato, T., Fujita, Y.

Nat. Cell Biol. 19 ( 5 ) 530 - 541 2017.05

Research paper (scientific journal), Joint Work, Accepted

Recent studies have revealed that newly emerging transformed cells are often apically extruded from epithelial tissues. During this process, normal epithelial cells can recognize and actively eliminate transformed cells, a process called epithelial defence against cancer (EDAC). Here, we show that mitochondrial membrane potential is diminished in RasV12-transformed cells when they are surrounded by normal cells. In addition, glucose uptake is elevated, leading to higher lactate production. The mitochondrial dysfunction is driven by upregulation of pyruvate dehydrogenase kinase 4 (PDK4), which positively regulates elimination of RasV12-transformed cells. Furthermore, EDAC from the surrounding normal cells, involving filamin, drives the Warburg-effect-like metabolic alteration. Moreover, using a cell-competition mouse model, we demonstrate that PDK-mediated metabolic changes promote the elimination of RasV12-transformed cells from intestinal epithelia. These data indicate that non-cell-autonomous metabolic modulation is a crucial regulator for cell competition, shedding light on the unexplored events at the initial stage of carcinogenesis.

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Succinate dehydrogenase B-deficient cancer cells are highly sensitive to bromodomain and extra-terminal inhibitors

Kitazawa, S., Ebara, S., Ando, A., Baba, Y., Satomi, Y., Soga, T., Hara, T.

Oncotarget 8 ( 17 ) 28922 - 28938 2017.04

Research paper (scientific journal), Joint Work, Accepted

Mutations in succinate dehydrogenase B (SDHB) gene are frequently observed in several tumors and associated with poor prognosis in these tumors. Therefore, drugs effective for SDHB-deficient tumors could fulfill an unmet medical need. In addition, such drugs would have an advantage in that selection of patients with SDHB-mutant cancer could increase the probability of success in clinical trials. Currently, however, the characteristics of SDHB-deficient cancers are not completely understood. Here, we established SDHB knockout cancer cell lines from human colon cancer HCT116 cells using the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 knockout system, and clarified its metabolic characteristics.In the SDHB knockout cells, succinate was accumulated and fumarate was decreased. The oxygen consumption rate was decreased while the extracellular acidification rate was increased in the SDHB knockout cells. Accordingly, an enhanced glycolysis pathway in the SDHB knockout cells was demonstrated by metabolomics analysis. Tracer experiments showed bidirectional metabolic flow in the tricarboxylic acid (TCA) cycle, possibly to maintain the necessary amounts of metabolites in the SDHB knockout cells. The proliferation of SDHB knockout cells was suppressed by a glycolysis inhibitor but not by a mitochondrial inhibitor. Additionally, partial dependence on glutaminolysis was observed in the SDHB knockout cells. Compound screening revealed that a bromodomain and extra-terminal (BET) inhibitor, which downregulated c-Myc, suppressed the growth of the SDHB knockout cells more potently than that of control cells. These findings provide an understanding of the metabolic characteristics of SDHB-deficient cancer and its vulnerabilities, which may lead to new therapeutic options.

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Remodelling of microRNAs in colorectal cancer by hypoxia alters metabolism profiles and 5-fluorouracil resistance

Nijhuis, A., Thompson, H., Adam, J., Paker A., Gammmon, L., Lewis, A., Bundy, J.G., Soga, T., Jalaly, A., Propper, D., Jeffery, R., Suraweera, N., McDonald, S., Thaha, M.A., Feakins, R., Lowe, R., Bishop, C., Silver, A.

Hum Mol Genet. 26 ( 8 ) 1552 - 1564 2017.04

Research paper (scientific journal), Joint Work, Accepted

Solid tumours have oxygen gradients and areas of near and almost total anoxia. Hypoxia reduces sensitivity to 5-fluorouracil (5-FU)-chemotherapy for colorectal cancer (CRC). MicroRNAs (miRNAs) are hypoxia sensors and were altered consistently in six CRC cell lines (colon cancer: DLD-1, HCT116 and HT29; rectal cancer: HT55, SW837 and VACO4S) maintained in hypoxia (1 and 0.2% oxygen) compared with normoxia (20.9%). CRC cell lines also showed altered amino acid metabolism in hypoxia and hypoxia-responsive miRNAs were predicted to target genes in four metabolism pathways: beta-alanine; valine, leucine, iso-leucine; aminoacyl-tRNA; and alanine, aspartate, glutamate. MiR-210 was increased in hypoxic areas of CRC tissues and hypoxia-responsive miR-21 and miR-30d, but not miR-210, were significantly increased in 5-FU resistant CRCs. Treatment with miR-21 and miR-30d antagonists sensitized hypoxic CRC cells to 5-FU. Our data highlight the complexity and tumour heterogeneity caused by hypoxia. MiR-210 as a hypoxic biomarker, and the targeting of miR-21 and miR-30d and/or the amino acid metabolism pathways may offer translational opportunities.

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Serum Metabolomic Profiles for Human Pancreatic Cancer Discrimination

Itoi, T., Sugimoto, M., Umeda, J., Sofuni, A., Tsuchiya, T., Tsuji, S., Tanaka, R., Tonozuka, R., Honjo, M., Moriyasu, F., Kasuya, K., Nagakawa, Y., Abe, Y., Takano, K., Kawachi, S., Shimazu, M., Soga, T., Tomita, M., Sunamura, M.

Int. J. Mol. Sci. 18 ( 4 ) 767 2017.04

Research paper (scientific journal), Joint Work, Accepted

This study evaluated the clinical use of serum metabolomics to discriminate malignant cancers including pancreatic cancer (PC) from malignant diseases, such as biliary tract cancer (BTC), intraductal papillary mucinous carcinoma (IPMC), and various benign pancreaticobiliary diseases. Capillary electrophoresismass spectrometry was used to analyze charged metabolites. We repeatedly analyzed serum samples (n = 41) of different storage durations to identify metabolites showing high quantitative reproducibility, and subsequently analyzed all samples (n = 140). Overall, 189 metabolites were quantified and 66 metabolites had a 20% coefficient of variation and, of these, 24 metabolites showed significant differences among control, benign, and malignant groups (p < 0.05; Steel-Dwass test). Four multiple logistic regression models (MLR) were developed and one MLR model clearly discriminated all disease patients from healthy controls with an area under receiver operating characteristic curve (AUC) of 0.970 (95% confidential interval (CI), 0.946-0.994, p < 0.0001). Another model to discriminate PC from BTC and IPMC yielded AUC = 0.831 (95% CI, 0.650-1.01, p = 0.0020) with higher accuracy compared with tumor markers including carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), pancreatic cancer-associated antigen (DUPAN2) and s-pancreas-1 antigen (SPAN1). Changes in metabolomic profiles might be used to screen for malignant cancers as well as to differentiate between PC and other malignant diseases.

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Sodium chloride promotes tissue inflammation via osmotic stimuli in subtotal-nephrectomized mice

Sakata, F., Ito, Y., Mizuno, M., Sawai, A., Suzuki, Y., Tomita, T., Tawada, M., Tanaka, A., Hirayama, A., Sagara, A., Wada, T., Maruyama, S., Soga, T., Matsuo, S., Imai, E., Takei, Y.

Lab. Invest. 97 ( 4 ) 432 - 446 2017.04

Research paper (scientific journal), Joint Work, Accepted

Chronic inflammation, which is often associated with high all-cause and cardiovascular mortality, is prevalent in patients with renal failure; however, the precise mechanisms remain unclear. High-salt intake was reported to induce lymphangiogenesis and autoimmune diseases via osmotic stimuli with accumulation of sodium or chloride. In addition, sodium was recently reported to be stored in the extremities of dialysis patients. We studied the effects and mechanisms of high salt loading on tissue and systemic inflammation in subtotal-nephrectomized mice (5/6Nx) and in cultured cells. Macrophage infiltration in the peritoneal wall (P<0.001), heart (P<0.05) and para-aortic tissues (P<0.001) was significantly higher in 5/6Nx with salt loading (5/6Nx/NaCl) than in 5/6Nx without salt loading (5/6Nx/Water); however, there were no significant differences in blood pressure and renal function between the groups. Tissue interleukin-6, monocyte chemotactic protein-1 (MCP-1), serum- and glucocorticoid-inducible kinase 1 (Sgk1) and tonicity-responsive enhancer binding protein (TonEBP) mRNA were significantly elevated in the peritoneal wall and heart with 5/6Nx/NaCl when compared with 5/6Nx/Water. Sodium was stored in the abdominal wall, exerting high-osmotic conditions. Reversal of salt loading reduced macrophage infiltration associated with decreased TonEBP in 5/6Nx/NaCl. Macrophage infiltration associated with fibrosis induced by salt loading was decreased in the 5/6Nx/NaCl/CC chemokine receptor 2 (CCR2, receptor of MCP-1)-deficient mice when compared with 5/6Nx/NaCl/Wild mice, suggesting that CCR2 is required for macrophage infiltration in 5/6Nx with NaCl loading. In cultured mesothelial cells and cardiomyocytes, culture media with high NaCl concentration induced MCP-1, Sgk1 and TonEBP mRNA, all of which were suppressed by TonEBP siRNA, indicating that both MCP-1 and Sgk1 are downstream of TonEBP. Our study indicates that high NaCl intake induces MCP-1 expression leading to macrophage infiltration via the TonEBP-MCP-1 pathway in 5/6Nx/NaCl mice, and that TonEBP has a central role in inflammation in patients with renal failure taking high salt.

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A serum metabolomics-based profile in low bone mineral density postmenopausal women

Miyamoto, T., Hirayama, A., Sato, Y., Koboyashi, T., Katsuyama, E., Kanagawa, H., Miyamoto, H., Mori, T., Yoshida, S., Fujie, A., Morita, M., Watanabe, R., Tando, T., Miyamoto, K., Tsuji, T., Funayama, A., Nakamura, M., Matsumoto, M., Soga, T., Tomita, M., Toyama, Y.

Bone 95 1 - 4 2017.02

Research paper (scientific journal), Accepted

Osteoporosis is characterized as a metabolic disorder of bone tissue, and various metabolic markers are now available to support its diagnosis and evaluate treatment effects. Substances produced as end products of metabolomic activities are the correlated factors to the biological or metabolic status, and thus, metabolites are considered highly sensitive markers of particular pathological states, including osteoporosis. Here we undertook comprehensive serum metabolomics analysis in postmenopausal women with or without low bone mineral density (low BMD vs controls) for the first time using capillary electrophoresis/mass spectrometry. Among the metabolites tested, 57 were detected in sera. Levels of hydroxyproline, Gly-Gly and cystine, differed significantly between groups, with Gly-Gly and cystine significantly lower in the low BMD group and hydroxyproline, a reported marker of osteoporosis, significantly higher. Levels of TRACP5b, a bone resorption marker, were significantly higher in the low BMD group, supporting the study's validity. Taken together, our findings represent novel metabolomic profiling in low BMD in postmenopausal women.

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Metabolomic profiling as a possible reverse engineering tool for estimating processing conditions of dry-cured hams

Sugimoto, M., Obiya, S., Kaneko, M., Enomoto, A., Honma, M., Wakayama, M., Soga, T., Tomita, M.

J. Agric. Food Chem 65 ( 2 ) 402 - 410 2017.01

Research paper (scientific journal), Joint Work, Accepted

Dry-cured hams are popular among consumers. To increase the attractiveness of the product, objective analytical methods and algorithms to evaluate the relationship between observable properties and consumer acceptability are required. In this study, metabolomics, which is used for quantitative profiling of hundreds of small molecules, was applied to 12 kinds of dry-cured hams from Japan and Europe. In total, 203 charged metabolites, including amino acids, organic acids, nucleotides, and peptides, were successfully identified and quantified. Metabolite profiles were compared for the samples with different countries of origin and processing methods (e.g., smoking or use of a starter culture). Principal component analysis of the metabolite profiles with sensory properties revealed significant correlations for redness, homogeneity, and fat whiteness. This approach could be used to design new ham products by objective evaluation of various features.

Stimulating S-adenosyl-L-methionine synthesis extends lifespan via activation of AMPK

Ogawa, T., Tsubakiyama, R., Kanai, M., Koyama , T., Fujii, T., Iefuji, H., Soga, T., Kume, K., Miyakawa, T., Hirata, D., Mizunuma, M.

Proc. Natl. Acad. Sci. USA 113 ( 42 ) 11913 - 11918 2016.10

Research paper (scientific journal), Joint Work, Accepted

Dietary restriction (DR), such as calorie restriction (CR) or methionine (Met) restriction, extends the lifespan of diverse model organisms. Although studies have identified several metabolites that contribute to the beneficial effects of DR, the molecular mechanism underlying the key metabolites responsible for DR regimens is not fully understood. Here we show that stimulating S-adenosyl-l-methionine (AdoMet) synthesis extended the lifespan of the budding yeast Saccharomyces cerevisiae The AdoMet synthesis-mediated beneficial metabolic effects, which resulted from consuming both Met and ATP, mimicked CR. Indeed, stimulating AdoMet synthesis activated the universal energy-sensing regulator Snf1, which is the S. cerevisiae ortholog of AMP-activated protein kinase (AMPK), resulting in lifespan extension. Furthermore, our findings revealed that S-adenosyl-l-homocysteine contributed to longevity with a higher accumulation of AdoMet only under the severe CR (0.05% glucose) conditions. Thus, our data uncovered molecular links between Met metabolites and lifespan, suggesting a unique function of AdoMet as a reservoir of Met and ATP for cell survival.

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Metabolic Profiling of Total Physical Activity and Sedentary Behavior in Community-Dwelling Men

Fukai, K., Harada, S., Iida, M., Kuriara, A., Takeuchi, A., Kuwabara, K., Sugiyama, D., Okamura, T., Akiyama, M., Nishiwaki, Y., Oguma, Y., Suzuki, A., Suzuki, C, Hirayama, A., Sugimoto, M., Soga, T.,c Tomita, M., Takebayashi, T.

PLoS One 11 ( 10 ) e0164877 2016.10

Research paper (scientific journal), Joint Work, Accepted

Objective: Physical activity is known to be preventive against various non-communicable diseases. We investigated the relationship between daily physical activity level and plasma metabolites using a targeted metabolomics approach in a population-based study.
Methods: A total of 1,193 participants (male, aged 35 to 74 years) with fasting blood samples were selected from the baseline survey of a cohort study. Information on daily total physical activity, classified into four levels by quartile of metabolic equivalent scores, and sedentary behavior, defined as hours of sitting per day, was collected through a self-administered questionnaire. Plasma metabolite concentrations were quantified by capillary electrophoresis mass spectrometry method. We performed linear regression analysis models with multivariable adjustment and corrected p-values for multiple testing in the original population (n = 808). The robustness of the results was confirmed by replication analysis in a separate population (n = 385) created by random allocation.
Results: Higher levels of total physical activity were associated with various metabolite concentrations, including lower concentrations of amino acids and their derivatives, and higher concentrations of pipecolate (FDR p <0.05 in original population). The findings persisted after adjustment for age, body mass index, smoking, alcohol intake, and energy intake. Isoleucine, leucine, valine, 4-methyl-2-oxoisopentanoate, 2-oxoisopentanoate, alanine, and proline concentrations were lower with a shorter sitting time.
Conclusions: Physical activity is related to various plasma metabolites, including known biomarkers for future insulin resistance or type 2 diabetes. These metabolites might potentially play a key role in the protective effects of higher physical activity and/or less sedentary behavior on non-communicable diseases.

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Index markers of chronic fatigue syndrome with dysfunction of TCA and urea cycles

Yamano, E., Sugimoto, M., Hirayama, A., Kume, S., Yamato, M., Jin, G., Tajima, S., Goda, N., Iwai, K., Fukuda, S., Yamaguti, K, Kuratsune, H., Soga, T., Watanabe, Y., Kataoka, Y.

Sci Rep. 6 34990 2016.10

Research paper (scientific journal), Joint Work, Accepted

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Expression of Idh1R132H in the murine subventricular zone stem cell niche recapitulates features of early gliomagenesis

Bardella C, Al-Dalahmah O, Krell D, Brazauskas P, Al-Qahtani K, Tomkova M, Adam J, Serres S, Lockstone H, Freeman-Mills L, Pfeffer I, Sibson N, Goldin R, Schuster-Böeckler B, Pollard, PJ, Soga T, McCullagh JS, Schofield CJ, Mulholland P, Ansorge O, Kriaucionis S, Ratcliffe PJ, Szele, FG, Tomlinson I

Cancer Cell 30 ( 4 ) 578 - 594 2016.10

Research paper (scientific journal), Joint Work

Isocitrate dehydrogenase 1 mutations drive human gliomagenesis, probably through neomorphic enzyme activity that produces D-2-hydroxyglutarate. To model this disease, we conditionally expressed Idh1R132H in the subventricular zone (SVZ) of the adult mouse brain. The mice developed hydrocephalus and grossly dilated lateral ventricles, with accumulation of 2-hydroxyglutarate and reduced α-ketoglutarate. Stem and transit amplifying/progenitor cell populations were expanded, and proliferation increased. Cells expressing SVZ markers infiltrated surrounding brain regions. SVZ cells also gave rise to proliferative subventricular nodules. DNA methylation was globally increased, while hydroxymethylation was decreased. Mutant SVZ cells overexpressed Wnt, cell-cycle and stem cell genes, and shared an expression signature with human gliomas. Idh1R132H mutation in the major adult neurogenic stem cell niche causes a phenotype resembling gliomagenesis.

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Therapeutic Strategy for Targeting Aggressive Malignant Gliomas by Disrupting Their Energy Balance

Hegazy, A.M., Yamada, D., Kobayashi, M., Kohno, S., Ueno, M., Ali, MA., Ohta, K., Tadokoro, Y., Ino, Y., Todo, T., Soga, T., Takahashi, C., Hirao, A.

J. Biol. Chem. 291 ( 41 ) 21496 - 21509 2016.10

Research paper (scientific journal), Joint Work, Accepted

Although abnormal metabolic regulation is a critical determinant of cancer cell behavior, it is still unclear how an altered balance between ATP production and consumption contributes to malignancy. Here we show that disruption of this energy balance efficiently suppresses aggressive malignant gliomas driven by mammalian target of rapamycin complex 1 (mTORC1) hyperactivation. In a mouse glioma model, mTORC1 hyperactivation induced by conditional Tsc1 deletion increased numbers of glioma-initiating cells (GICs) in vitro and in vivo Metabolic analysis revealed that mTORC1 hyperactivation enhanced mitochondrial biogenesis, as evidenced by elevations in oxygen consumption rate and ATP production. Inhibition of mitochondrial ATP synthetase was more effective in repressing sphere formation by Tsc1-deficient glioma cells than that by Tsc1-competent glioma cells, indicating a crucial function for mitochondrial bioenergetic capacity in GIC expansion. To translate this observation into the development of novel therapeutics targeting malignant gliomas, we screened drug libraries for small molecule compounds showing greater efficacy in inhibiting the proliferation/survival of Tsc1-deficient cells compared with controls. We identified several compounds able to preferentially inhibit mitochondrial activity, dramatically reducing ATP levels and blocking glioma sphere formation. In human patient-derived glioma cells, nigericin, which reportedly suppresses cancer stem cell properties, induced AMPK phosphorylation that was associated with mTORC1 inactivation and induction of autophagy and led to a marked decrease in sphere formation with loss of GIC marker expression. Furthermore, malignant characteristics of human glioma cells were markedly suppressed by nigericin treatment in vivo Thus, targeting mTORC1-driven processes, particularly those involved in maintaining a cancer cell's energy balance, may be an effective therapeutic strategy for glioma patients.

Identification of salivary metabolomic biomarkers for oral cancer screening

Ishikawa, S., Sugimoto, M., Kitabatake, K., Sugano, A., Nakamura, M., Kaneko, M., Ota, S., Hiwatari, K., Enomoto, A., Soga, T., Tomita, M., Iino, M.

Sci. Rep. 6 ( - ) 31520 - - 2016.08

Research paper (scientific journal), Joint Work, Accepted

The objective of this study was to explore salivary metabolite biomarkers by profiling both saliva and tumor tissue samples for oral cancer screening. Paired tumor and control tissues were obtained from oral cancer patients and whole unstimulated saliva samples were collected from patients and healthy controls. The comprehensive metabolomic analysis for profiling hydrophilic metabolites was conducted using capillary electrophoresis time-of-flight mass spectrometry. In total, 85 and 45 metabolites showed significant differences between tumor and matched control samples, and between salivary samples from oral cancer and controls, respectively (P < 0.05 correlated by false discovery rate); 17 metabolites showed consistent differences in both saliva and tissue-based comparisons. Of these, a combination of only two biomarkers yielded a high area under receiver operating characteristic curves (0.827; 95% confidence interval, 0.726-0.928, P < 0.0001) for discriminating oral cancers from controls. Various validation tests confirmed its high generalization ability. The demonstrated approach, integrating both saliva and tumor tissue metabolomics, helps eliminate pseudo-molecules that are coincidentally different between oral cancers and controls. These combined salivary metabolites could be the basis of a clinically feasible method of non-invasive oral cancer screening.

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p38α activates purine metabolism to initiate hematopoietic stem/progenitor cell cycling in response to stress

Karigane, D., Kobayashi, H., Morikawa, T., Ootomo, Y., Sakai, M., Nagamatsu, G., Kubota, Y., Goda, N., Matsumoto, M., Nishimura, E. K., Soga, T., Otsu, K., Suematsu, M., Okamoto, S., Suda, T., Takubo, K.

Cell Stem Cell 19 ( 2 ) 192 - 204 2016.08

Research paper (scientific journal), Joint Work

Hematopoietic stem cells (HSCs) maintain quiescence by activating specific metabolic pathways, including glycolysis. We do not yet have a clear understanding of how this metabolic activity changes during stress hematopoiesis, such as bone marrow transplantation. Here, we report a critical role for the p38MAPK family isoform p38α in initiating hematopoietic stem and progenitor cell (HSPC) proliferation during stress hematopoiesis in mice. We found that p38MAPK is immediately phosphorylated in HSPCs after a hematological stress, preceding increased HSPC cycling. Conditional deletion of p38α led to defective recovery from hematological stress and a delay in initiation of HSPC proliferation. Mechanistically, p38α signaling increases expression of inosine-5'-monophosphate dehydrogenase 2 in HSPCs, leading to altered levels of amino acids and purine-related metabolites and changes in cell-cycle progression in vitro and in vivo. Our studies have therefore uncovered a p38α-mediated pathway that alters HSPC metabolism to respond to stress and promote recovery.

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Mitochondrial Mg2+ homeostasis decides cellular energy metabolism and vulnerability to stress

Yamanaka, R., Tabata, S., Shindo, Y., Hotta, K., Suzuki, K., Soga, T., Oka, K.

Sci. Rep. 6 30027 2016.07

Research paper (scientific journal), Joint Work, Accepted

Cellular energy production processes are composed of many Mg(2+) dependent enzymatic reactions. In fact, dysregulation of Mg(2+) homeostasis is involved in various cellular malfunctions and diseases. Recently, mitochondria, energy-producing organelles, have been known as major intracellular Mg(2+) stores. Several biological stimuli alter mitochondrial Mg(2+) concentration by intracellular redistribution. However, in living cells, whether mitochondrial Mg(2+) alteration affect cellular energy metabolism remains unclear. Mg(2+) transporter of mitochondrial inner membrane MRS2 is an essential component of mitochondrial Mg(2+) uptake system. Here, we comprehensively analyzed intracellular Mg(2+) levels and energy metabolism in Mrs2 knockdown (KD) cells using fluorescence imaging and metabolome analysis. Dysregulation of mitochondrial Mg(2+) homeostasis disrupted ATP production via shift of mitochondrial energy metabolism and morphology. Moreover, Mrs2 KD sensitized cellular tolerance against cellular stress. These results indicate regulation of mitochondrial Mg(2+) via MRS2 critically decides cellular energy status and cell vulnerability via regulation of mitochondrial Mg(2+) level in response to physiological stimuli.

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Serum metabolome profiles characterized by patients with hepatocellular carcinoma associated with hepatitis B and C

Saito, T., Sugimoto, M., Okumoto, K., Haga, H., Katsumi, T., Mizuno, K., Nishina, T., Sato, S., Igarashi, K., Maki, H., Tomita, M., Ueno, Y., Soga, T.

World J. Gastroenterol. 22 ( 27 ) 6224 - 6234 2016.07

Research paper (scientific journal), Joint Work

Aim: To clarify the characteristics of metabolite profiles in virus-related hepatocellular carcinoma (HCC) patients using serum metabolome analysis.
Methods: The serum levels of low-molecular-weight metabolites in 68 patients with HCC were quantified using capillary electrophoresis chromatography and mass spectrometry. Thirty and 38 of the patients suffered from hepatitis B virus-related HCC (HCC-B) and hepatitis C virus-related HCC (HCC-C), respectively.
Results: The main metabolites characteristic of HCC were those associated with glutathione metabolism, notably 13 γ-glutamyl peptides, which are by-products of glutathione induction. Two major profiles, i.e., concentration patterns, of metabolites were identified in HCC patients, and these were classified into two groups: an HCC-B group and an HCC-C group including some of the HCC-B cases. The receiver operating characteristic curve for the multiple logistic regression model discriminating HCC-B from HCC-C incorporating the concentrations of glutamic acid, methionine and γ-glutamyl-glycine-glycine showed a highly significant area under the curve value of 0.94 (95%CI: 0.89-1.0, P < 0.0001).

Conclusion: The serum levels of γ-glutamyl peptides, as well as their concentration patterns, contribute to the development of potential biomarkers for virus-related HCC. The difference in metabolite profiles between HCC-B and HCC-C may reflect the respective metabolic reactions that underlie the different pathogeneses of these two types of HCC.

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Profiling of plasma metabolites in postmenopausal women with metabolic syndrome

Iida, M., Harada, S., Kurihara, A., Fukai, K., Kuwabara, K., Sugiyama, D., Takeuchi, A., Okamura, T., Akiyama, M., Nishiwaki, Y., Suzuki, A., Hirayama, A., Sugimoto, M., Soga, T., Tomita, M., Banno, K., Aoki, D., Takebayashi, T.

Menopause 23 ( 7 ) 749 - 758 2016.07

Research paper (scientific journal), Joint Work, Accepted

Objective: The aim of the study was to investigate the associations of amino acids and other polar metabolites with metabolic syndrome (MetS) in postmenopausal women in a lean Asian population.
Methods: The participants were 1,422 female residents enrolled in a cohort study from April to August 2012. MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III modified for Japanese women. Associations were examined between MetS and 78 metabolites assayed in fasting plasma samples using capillary electrophoresis-mass spectrometry. Replication analysis was performed to confirm the robustness of the results in a separate population created by random allocation.
Results: Analysis was performed for 877 naturally postmenopausal women, including 594 in the original population and 283 in the replication population. The average age, body mass index, and levels of high- and low-density lipoprotein cholesterol of the entire population were 64.6 years, 23.0 kg/m, 72.1 mg/dL, and 126.1 mg/dL, respectively. There was no significant difference in low-density lipoprotein cholesterol levels between women with and without MetS. Thirteen metabolites were significantly related to MetS: multiple plasma amino acids were elevated in women with MetS, including branched-chain amino acids, alanine, glutamate, and proline; and alpha-aminoadipate, which is generated by lysine degradation, was also significantly increased.
Conclusions: Our large-scale metabolomic profiling indicates that Japanese postmenopausal women with MetS have abnormal polar metabolites, suggesting altered catabolic pathways. These results may help to understand metabolic disturbance, including in persons with normal body mass index and relatively high levels of high-density lipoprotein cholesterol, and may have clinical utility based on further studies.

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p62/Sqstm1 promotes malignancy of HCV-positive hepatocellular carcinoma through Nrf2-dependent metabolic reprogramming

Saito, T., Ichimura, Y., Taguchi, K., Suzuki, T., Mizushima, T., Takagi, K., Hirose, Y., Nagahashi, M., Iso, T., Fukutomi, T., Ohishi, M., Endo, K., Uemura, T., Nishito, Y., Okuda, S., Obata, M., Kouno, T., Imamura, R., Tada, Y., Obata, R., Yasuda, D., Takahashi, K., Fujimura, T., Pi, J., Lee, MS., Ueno, T., Ohe, T., Mashino, T., Wakai, T., Kojima, H., Okabe, T., Nagano, T., Motohashi, H., Waguri, S., Soga, T., Yamamoto, M., Tanaka, K., Komatsu, M.

Nat. Commun. 7 12030 2016.06

Research paper (scientific journal), Joint Work

p62/Sqstm1 is a multifunctional protein involved in cell survival, growth and death, that is degraded by autophagy. Amplification of the p62/Sqstm1 gene, and aberrant accumulation and phosphorylation of p62/Sqstm1, have been implicated in tumour development. Herein, we reveal the molecular mechanism of p62/Sqstm1-dependent malignant progression, and suggest that molecular targeting of p62/Sqstm1 represents a potential chemotherapeutic approach against hepatocellular carcinoma (HCC). Phosphorylation of p62/Sqstm1 at Ser349 directs glucose to the glucuronate pathway, and glutamine towards glutathione synthesis through activation of the transcription factor Nrf2. These changes provide HCC cells with tolerance to anti-cancer drugs and proliferation potency. Phosphorylated p62/Sqstm1 accumulates in tumour regions positive for hepatitis C virus (HCV). An inhibitor of phosphorylated p62-dependent Nrf2 activation suppresses the proliferation and anticancer agent tolerance of HCC. Our data indicate that this Nrf2 inhibitor could be used to make cancer cells less resistant to anticancer drugs, especially in HCV-positive HCC patients.

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