Papers - Soga, Tomoyoshi

Genetic, metabolomic and transcriptomic analyses of the de novo L-cysteine biosynthetic pathway in the enteric protozoan parasite Entamoeba histolytica

Jeelani, G., Sato, D., Soga, T., Nozaki, T.

Sci. Rep. 7 ( 1 ) 15649 2017.11

Research paper (scientific journal), Joint Work, Accepted

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The de novo L-cysteine biosynthetic pathway is critical for the growth, antioxidative stress defenses, and pathogenesis of bacterial and protozoan pathogens, such as Salmonella typhimurium and Entamoeba histolytica. This pathway involves two key enzymes, serine acetyltransferase (SAT) and cysteine synthase (CS), which are absent in mammals and therefore represent rational drug targets. The human parasite E. histolytica possesses three SAT and CS isozymes; however, the specific roles of individual isoforms and significance of such apparent redundancy remains unclear. In the present study, we generated E. histolytica cell lines in which CS and SAT expression was knocked down by transcriptional gene silencing. The strain in which CS1, 2 and 3 were simultaneously silenced and the SAT3 gene-silenced strain showed impaired growth when cultured in a cysteine lacking BI-S-33 medium, whereas silencing of SAT1 and SAT2 had no effects on growth. Combined transcriptomic and metabolomic analyses revealed that, CS and SAT3 are involved in S-methylcysteine/cysteine synthesis. Furthermore, silencing of the CS1-3 or SAT3 caused upregulation of various iron-sulfur flavoprotein genes. Taken together, these results provide the first direct evidence of the biological importance of SAT3 and CS isoforms in E. histolytica and justify the exploitation of these enzymes as potential drug targets.

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ACSL3 promotes intratumoral steroidogenesis in prostate cancer cells

Migita, T., Takayama, K., Urano, T., Obinata, D., Ikeda, K., Soga, T., Takahashi, S., Inoue, S.

Cancer Sci. 108 ( 10 ) 2011 - 2021 2017.10

Research paper (scientific journal), Joint Work, Accepted

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Long-chain acyl-coenzyme A (CoA) synthetase 3 (ACSL3) is an androgen-responsive gene involved in the generation of fatty acyl-CoA esters. ACSL3 is expressed in both androgen-sensitive and castration-resistant prostate cancer (CRPC). However, its role in prostate cancer remains elusive. We overexpressed ACSL3 in androgen-dependent LNCaP cells and examined the downstream effectors of ACSL3. Furthermore, we examined the role of ACSL3 in the androgen metabolism of prostate cancer. ACSL3 overexpression led to upregulation of several genes such as aldo-keto reductase 1C3 (AKR1C3) involved in steroidogenesis, which utilizes adrenal androgen dehydroepiandrosterone sulfate (DHEAS) as substrate, and downregulated androgen-inactivating enzyme UDP-glucuronosyltransferase 2 (UGT2B). Exposure to DHEAS significantly increased testosterone levels and cell proliferative response in ACSL3-overexpressing cells when compared to that in control cells. A public database showed that ACSL3 level was higher in CRPC than in hormone-sensitive prostate cancer. CRPC cells showed an increased expression of ACSL3 and an expression pattern of AKR1C3 and UGT2B similar to ACSL3-overexpressing cells. DHEAS stimulation significantly promoted the proliferation of CRPC cells when compared to that of LNCaP cells. These findings suggest that ACSL3 contributes to the growth of CRPC through intratumoral steroidogenesis (i.e. promoting androgen synthesis from DHEAS and preventing the catabolism of active androgens).

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Fumarate hydratase deletion in pancreatic β cells leads to progressive diabetes

Adam, J., Ramracheya, R., Chibalina, M.V., Ternette, N., Hamilton, A., Tarasov, A.I., Zhang, Q., Rebelato, E., Rorsman, N.J.G., Martin-del-Rio, R., Lewis, A., Ozkan, G., Do, H.W., Spegal, P., Saitoh, K., Kato, K., Igarashi, K., Kessler, B.M., Pugh, C.W., Tamarit-Rodriques, J., Mulder, H., Clark, A., Fizzell, N., Soga, T., Ashcroft, F.M., Silver, A., Pollard, P.J., Rorsman, P.

Cell Rep. 20 ( 13 ) 3135 - 3148 2017.09

Research paper (scientific journal), Joint Work, Accepted

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We explored the role of the Krebs cycle enzyme fumarate hydratase (FH) in glucose-stimulated insulin secretion (GSIS). Mice lacking Fh1 in pancreatic β cells (Fh1βKO mice) appear normal for 6-8 weeks but then develop progressive glucose intolerance and diabetes. Glucose tolerance is rescued by expression of mitochondrial or cytosolic FH but not by deletion of Hif1α or Nrf2. Progressive hyperglycemia in Fh1βKO mice led to dysregulated metabolism in β cells, a decrease in glucose-induced ATP production, electrical activity, cytoplasmic [Ca2+]i elevation, and GSIS. Fh1 loss resulted in elevated intracellular fumarate, promoting succination of critical cysteines in GAPDH, GMPR, and PARK 7/DJ-1 and cytoplasmic acidification. Intracellular fumarate levels were increased in islets exposed to high glucose and in islets from human donors with type 2 diabetes (T2D). The impaired GSIS in islets from diabetic Fh1βKO mice was ameliorated after culture under normoglycemic conditions. These studies highlight the role of FH and dysregulated mitochondrial metabolism in T2D.

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Global metabolic reprogramming of colorectal cancer occurs at adenoma stage and is induced by MYC

Satoh, K., Yachida, S., Sugimoto, M., Oshima, M., Nakagawa, T., Akamoto, S., Tabata, S., Saitoh, K., Kato, K., Sato, S., Igarashi, K., Aizawa, Y., Kajino-Sakamoto, R., Kojima, Y., Fujishita, T., Enomoto, A., Hirayama, A., Ishikawa, T., Taketo, M.M., Kushida, Y., Haba, R., Okano, K., Tomita, M., Suzuki, Y., Fukuda, S., Aoki, M., Soga, T.

Proc. Natl. Acad. Sci. USA 114 ( 37 ) E7697 - E7706 2017.09

Research paper (scientific journal), Joint Work, Accepted

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Cancer cells alter their metabolism for the production of precursors of macromolecules. However, the control mechanisms underlying this reprogramming are poorly understood. Here we show that metabolic reprogramming of colorectal cancer is caused chiefly by aberrant MYC expression. Multiomics-based analyses of paired normal and tumor tissues from 275 patients with colorectal cancer revealed that metabolic alterations occur at the adenoma stage of carcinogenesis, in a manner not associated with specific gene mutations involved in colorectal carcinogenesis. MYC expression induced at least 215 metabolic reactions by changing the expression levels of 121 metabolic genes and 39 transporter genes. Further, MYC negatively regulated the expression of genes involved in mitochondrial biogenesis and maintenance but positively regulated genes involved in DNA and histone methylation. Knockdown of MYC in colorectal cancer cells reset the altered metabolism and suppressed cell growth. Moreover, inhibition of MYC target pyrimidine synthesis genes such as CAD, UMPS, and CTPS blocked cell growth, and thus are potential targets for colorectal cancer therapy.

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Evaluation of the impact of gut microbiota on uremic solute accumulation by CE-TOFMS-based metabolomics approach

Mishima, E., Fukuda, S. (equally contributed), Mukawa, C., Yuri, A., Kanemitsu, Y., Matsumoto, Y., Akiyama, Y., Fukuda, NN., Tsukamoto, H., Asaji, K., Shima, H., Kikuchi, K., Suzuki, T., Tomioka, Y., Soga, T., Ito, S., Abe, T.

Kidney Int. 92 ( 3 ) 634 - 645 2017.09

Research paper (scientific journal), Joint Work

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Gut microbiota is involved in the metabolism of uremic solutes. However, the precise influence of microbiota to the retention of uremic solutes in CKD is obscure. To clarify this, we compared adenine-induced renal failure and control mice under germ-free or specific pathogen-free (SPF) conditions, examining the metabolite profiles of plasma, feces, and urine using a capillary electrophoresis time-of-flight mass spectrometry-based approach. Mice with renal failure under germ-free conditions demonstrated significant changes in plasma metabolites. Among 183 detected solutes, plasma levels of 11 solutes, including major uremic toxins, were significantly lower in germ-free mice than in SPF mice with renal failure. These 11 solutes were considered microbiota-derived uremic solutes and included indoxyl sulfate, p-cresyl sulfate, phenyl sulfate, cholate, hippurate, dimethylglycine, γ-guanidinobutyrate, glutarate, 2-hydroxypentanoate, trimethylamine N-oxide, and phenaceturate. Metabolome profiling showed that these solutes were classified into three groups depending on their origins: completely derived from microbiota (indoxyl sulfate, p-cresyl sulfate), derived from both host and microbiota (dimethylglycine), and derived from both microbiota and dietary components (trimethylamine N-oxide). Additionally, germ-free renal failure conditions resulted in the disappearance of colonic short-chain fatty acids, decreased utilization of intestinal amino acids, and more severe renal damage compared with SPF mice with renal failure. Microbiota-derived short-chain fatty acids and efficient amino acid utilization may have a renoprotective effect, and loss of these factors may exacerbate renal damage in germ-free mice with renal failure. Thus, microbiota contributes substantially to the production of harmful uremic solutes, but conversely, growth without microbiota has harmful effects on CKD progression.

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Effect of masticatory stimulation on the quantity and quality of saliva and the salivary metabolomic profile

Okuma, N., Saita, M., Hoshi, N., Soga, T., Tomita, M., Sugimoto, M., Kimoto, K.

PLoS One 12 ( 8 ) e0183109 2017.08

Research paper (scientific journal), Joint Work, Accepted

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Background: This study characterized the changes in quality and quantity of saliva, and changes in the salivary metabolomic profile, to understand the effects of masticatory stimulation.
Methods: Stimulated and unstimulated saliva samples were collected from 55 subjects and salivary hydrophilic metabolites were comprehensively quantified using capillary electrophoresis-time-of-flight mass spectrometry.
Results: In total, 137 metabolites were identified and quantified. The concentrations of 44 metabolites in stimulated saliva were significantly higher than those in unstimulated saliva. Pathway analysis identified the upregulation of the urea cycle and synthesis and degradation pathways of glycine, serine, cysteine and threonine in stimulated saliva. A principal component analysis revealed that the effect of masticatory stimulation on salivary metabolomic profiles was less dependent on sample population sex, age, and smoking. The concentrations of only 1 metabolite in unstimulated saliva, and of 3 metabolites stimulated saliva, showed significant correlation with salivary secretion volume, indicating that the salivary metabolomic profile and salivary secretion volume were independent factors.
Conclusions: Masticatory stimulation affected not only salivary secretion volume, but also metabolite concentration patterns. A low correlation between the secretion volume and these patterns supports the conclusion that the salivary metabolomic profile may be a new indicator to characterize masticatory stimulation.

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Inhibition of dipeptidyl peptidase-4 ameliorates cardiac ischemia and systolic dysfunction by up-regulating the FGF-2/EGR-1 pathway

Suda, M., Shimizu, I. , Yoshida, Y., Hayashi, Y., Ikegami, R., Katsuumi, G., Wakasugi, T., Yoshida, Y., Okuda, S., Soga, T., Minamino, T.

PLoS One 12 ( 8 ) e0182422 2017.08

Research paper (scientific journal), Joint Work

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Dipeptidyl peptidase 4 inhibitors are used worldwide in the management of diabetes, but their role in the prevention or treatment of cardiovascular disorders has yet to be defined. We found that linagliptin, a DPP-4 inhibitor, suppressed capillary rarefaction in the hearts of mice with dietary obesity. Metabolomic analysis performed with capillary electrophoresis/mass spectrometry (LC-MS/MS) showed that linagliptin promoted favorable metabolic remodeling in cardiac tissue, which was characterized by high levels of citrulline and creatine. DNA microarray analysis revealed that the cardiac tissue level of early growth response protein 1 (EGR-1), which activates angiogenesis, was significantly reduced in untreated mice with dietary obesity, while this decrease was inhibited by administration of linagliptin. Mature fibroblast growth factor 2 (FGF-2) has a putative truncation site for DPP-4 at the NH2-terminal, and LC-MS/MS showed that recombinant DPP-4 protein cleaved the NH2-terminal dipeptides of mature FGF-2. Incubation of cultured neonatal rat cardiomyocytes with FGF-2 increased Egr1 expression, while it was suppressed by recombinant DPP-4 protein. Furthermore, vascular endothelial growth factor-A had a critical role in mediating FGF-2/EGR-1 signaling. In conclusion, pharmacological inhibition of DPP-4 suppressed capillary rarefaction and contributed to favorable remodeling of cardiac metabolism in mice with dietary obesity.

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Distinct requirements for energy metabolism in mouse primordial germ cells and their reprogramming to embryonic germ cells

Hayashi, Y., Otsuka, K., Ebina, M., Igarashi, K., Takehara, A., Matsumoto, M., Kanai, A., Igarashi, K., Soga, T., Matsui, Y.

Proc. Natl. Acad. Sci. USA 114 ( 31 ) 8289 - 8294 2017.08

Research paper (scientific journal), Joint Work, Accepted

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Primordial germ cells (PGCs), undifferentiated embryonic germ cells, are the only cells that have the ability to become gametes and to reacquire totipotency upon fertilization. It is generally understood that the development of PGCs proceeds through the expression of germ cell-specific transcription factors and characteristic epigenomic changes. However, little is known about the properties of PGCs at the metabolite and protein levels, which are directly responsible for the control of cell function. Here, we report the distinct energy metabolism of PGCs compared with that of embryonic stem cells. Specifically, we observed remarkably enhanced oxidative phosphorylation (OXPHOS) and decreased glycolysis in embryonic day 13.5 (E13.5) PGCs, a pattern that was gradually established during PGC differentiation. We also demonstrate that glycolysis and OXPHOS are important for the control of PGC reprogramming and specification of pluripotent stem cells (PSCs) into PGCs in culture. Our findings about the unique metabolic property of PGCs provide insights into our understanding of the importance of distinct facets of energy metabolism for switching PGC and PSC status.

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Metabolomics of an in vitro liver model containing primary hepatocytes assembling around an endothelial cell network: comparative study on the metabolic stability and the effect of acetaminophen treatment

Toyoda, Y., Kashikura, K., Soga, T., Tagawa, Y.

J. Toxicol. Sci. 42 ( 4 ) 445 - 454 2017.08

Research paper (scientific journal), Joint Work, Accepted

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Recently, a novel culture system consisting of primary hepatocytes structured over a network of endothelial cells on the Engelbreth-Holm-Swarm (EHS) gel has been reported. This in vitro liver model on the EHS gel (IVLEHS) has been shown to maintain the expression of hepatic genes and their functional activity. Moreover, the IVLEHS was more sensitive to xenobiotics than hepatocyte monocultures, suggesting the potential utility of this culture system for compound hepatotoxicity screening. However, the effect of this three-dimensional structure formation on the cellular metabolic profile of hepatocytes in the IVLEHS is not well understood. To address this concern, we performed metabolome analysis using capillary electrophoresis-time of flight mass spectrometry. Between the IVLEHS and mono-cultured hepatocytes on the EHS gel, there was no significant difference in the levels of metabolites of the urea cycle and the tricarboxylic acid cycle, essential amino acids, and adenylate energy charge (AEC) which is an important indicator of cellular energy status. On the other hand, acetaminophen-dependent decrease of the AEC in the IVLEHS was greater than that in the monoculture, suggesting the higher sensitivity of IVLEHS to acetaminophen-induced hepatotoxicity which is caused by metabolic activation of this drug. Further analysis showed that the levels of taurocholate, one of the major conjugated bile acids, were higher in the IVLEHS than in the monoculture. Considering that the construction of the IVLEHS did not seem to disturb the major cellular metabolism, our findings would strengthen the concept that IVLEHS would have beneficial effects on the maintenance of hepatic functions.

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Cancer with low cathepsin D levels is susceptible to vacuolar (H+)-ATPase inhibition

Kitazawa, S., Nishizawa, S., Nakagawa, H., Funata, M., Nishimura, K., Soga, T., Hara, T.

Cancer Sci. 108 ( 6 ) 1185 - 1193 2017.06

Research paper (scientific journal), Joint Work, Accepted

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Vacuolar (H+ )-ATPases (V-ATPases) have important roles in the supply of nutrients to tumors by mediating autophagy and the endocytic uptake of extracellular fluids. Accordingly, V-ATPases are attractive therapeutic targets for cancer. However, the clinical use of V-ATPase inhibitors as anticancer drugs has not been realized, possibly owing to their high toxicity in humans. Inhibition of V-ATPase may be an appropriate strategy in highly susceptible cancers. In this study, we explored markers of V-ATPase inhibitor sensitivity. V-ATPase inhibitors led to pH impairment in acidic intracellular compartments, suppression of macropinocytosis, and decreased intracellular amino acid levels. The sensitivity of cells to V-ATPase inhibitors was correlated with low cathepsin D expression, and cancer cells showed increased sensitivity to V-ATPase inhibitors after pretreatment with a cathepsin D inhibitor and siRNA targeting the cathepsin D gene (CTSD). In addition, V-ATPase inhibitor treatment led to the induction of the amino acid starvation response, upregulation of endoplasmic reticulum stress markers, and suppression of mammalian target of rapamycin (mTOR) signaling in cells expressing low levels of cathepsin D. Some colorectal cancer patients showed the downregulation of cathepsin D in tumor tissues compared with matched normal tissues. These findings indicate that V-ATPase inhibitors are promising therapeutic options for cancers with downregulated cathepsin D.

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The metabolic profile of a rat model of chronic kidney disease

Tanada, Y., Okuda, J., Kato, T., Minamino-Muta, E., Murata, I., Soga, T., Shioi, T., Kimura, T.

Peer J. 5   e3352 2017.05

Research paper (scientific journal), Joint Work, Accepted

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Background: The kidney is always subjected to high metabolic demand. The aim of this study was to characterize metabolic profiles of a rat model of chronic kidney disease (CKD) with cardiorenal syndrome (CRS) induced by prolonged hypertension.
Methods: We used inbred male Dahl salt-sensitive (DS) rats fed an 8% NaCl diet from six weeks of age (high-salt; HS group) or a 0.3% NaCl diet as controls (low-salt; LS group). We analyzed function, pathology, metabolome, and the gene expression related to energy metabolism of the kidney.
Results: DS rats with a high-salt diet showed hypertension at 11 weeks of age and elevated serum levels of creatinine and blood urea nitrogen with heart failure at 21 weeks of age. The fibrotic area in the kidneys increased at 21 weeks of age. In addition, gene expression related to mitochondrial function was largely decreased. The levels of citrate and isocitrate increased and the gene expression of alpha-ketoglutaratedehydrogenase and succinyl-CoA synthetase decreased; these are enzymes that metabolize citrate and isocitrate, respectively. In addition, the levels of succinate and acetyl Co-A, both of which are metabolites of the tricarboxylic acid (TCA) cycle, decreased.
Conclusions: DS rats fed a high-salt diet were deemed a suitable model of CKD with CRS. Gene expression and metabolites related to energy metabolism and mitochondria in the kidney significantly changed in DS rats with hypertension in accordance with the progression of renal injury.

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Synthetic Biomarker Design by Using Analyte-Responsive Acetaminophen

Nishihara, T., Inoue, J., Tabata, S., Murakami, S., Ishikawa, T., Saito, N., Fukuda, S., Tomita, M., Soga, T.

Chembiochem 18 ( 10 ) 910 - 913 2017.05

Research paper (scientific journal), Joint Work, Accepted

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The use of synthetic biomarkers is an emerging technique to improve disease diagnosis. Here, we report a novel design strategy that uses analyte-responsive acetaminophen (APAP) to expand the catalogue of analytes available for synthetic biomarker development. As proof-of-concept, we designed hydrogen peroxide (H2 O2 )-responsive APAP (HR-APAP) and succeeded in H2 O2 detection with cellular and animal experiments. In fact, for blood samples following HR-APAP injection, we demonstrated that the plasma concentration ratio [APAP+APAP conjugates]/[HR-APAP] accurately reflects in vivo differences in H2 O2 levels. We anticipate that our practical methodology will be broadly useful for the preparation of various synthetic biomarkers.

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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

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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

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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

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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

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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

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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

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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

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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

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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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