研究者詳細 - 佐谷　秀行

論文 - 佐谷　秀行

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Endothelial-mesenchymal transition drives expression of CD44 variant and xCT in pulmonary hypertension

Isobe S., Kataoka M., Endo J., Moriyama H., Okazaki S., Tsuchihashi K., Katsumata Y., Yamamoto T., Shirakawa K., Yoshida N., Shimoda M., Chiba T., Masuko T., Hakamata Y., Kobayashi E., Saya H., Fukuda K., Sano M.

American Journal of Respiratory Cell and Molecular Biology （American Journal of Respiratory Cell and Molecular Biology） 61 （ 3 ） 367 - 379 2019年

ISSN 10441549

© 2019 by the American Thoracic Society. Pulmonary arterial hypertension (PAH) pathogenesis shares similarities with carcinogenesis. One CD44 variant (CD44v) isoform, CD44v8-10, binds to and stabilizes the cystine transporter subunit (xCT), producing reduced glutathione and thereby enhancing the antioxidant defense of cancer stem cells. Pharmacological inhibition of xCT by sulfasalazine suppresses tumor growth, survival, and resistance to chemotherapy. We investigated whether the CD44v-xCT axis contributes to PAH pathogenesis. CD44v was predominantly expressed on endothelial-to-mesenchymal transition (EndMT)-like cells in the neointimal layer of PAH affected pulmonary arterioles. In vitro, CD44 standard form and CD44v were induced as a result of EndMT. Among human pulmonary artery endothelial cells that have undergone EndMT, CD44v+ cells showed high levels of xCT expression on their cell surfaces and high concentrations of glutathione for survival. This made CD44v+ cells the most vulnerable target for sulfasalazine. CD44v+xCThi cells showed the highest expression levels of proinflammatory cytokines, antioxidant enzymes, antiapoptotic molecules, and cyclin-dependent kinase inhibitors. In the Sugen5416/hypoxia mouse model, CD44v+ cells were present in the thickened pulmonary vascular wall. The administration of sulfasalazine started either at the same time as "Sugen5416" administration (a prevention model) or after the development of pulmonary hypertension (a reversal model) attenuated the muscularization of the pulmonary vessels, decreased the expression of markers of inflammation, and reduced the right ventricular systolic pressure, while reducing CD44v+ cells. In conclusion, CD44v+xCThi cells appear during EndMT and in pulmonary hypertension tissues. Sulfasalazine is expected to be a novel therapeutic agent for PAH, most likely targeting EndMT-derived CD44v+xCThi cells.

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Cancer Stem-Cell Marker CD44v9-Positive Cells Arise From Helicobacter pylori–Infected CAPZA1-Overexpressing Cells

Tsugawa H., Kato C., Mori H., Matsuzaki J., Kameyama K., Saya H., Hatakeyama M., Suematsu M., Suzuki H.

Cellular and Molecular Gastroenterology and Hepatology （Cellular and Molecular Gastroenterology and Hepatology） 8 （ 3 ） 319 - 334 2019年

© 2019 The Authors Background & Aims: CD44 variant 9 (CD44v9)-positive cancer stem-like cells strongly contribute to the development and recurrence of gastric cancer. However, the origin of CD44v9-positive cells is uncertain. Methods: CD44v9, β-catenin, and epithelial splicing regulatory protein 1 signals were assessed by real-time reverse-transcription polymerase chain reaction, immunoblot analysis, or immunofluorescence microscopy. Capping actin protein of muscle Z-line α subunit 1 (CAPZA1) expression was assessed by immunoblot analysis or immunohistochemical analysis of Mongolian gerbils' gastric mucosa or human biopsy specimens. Levels of oxidative stress were assessed by measuring malondialdehyde and protein carbonylation. Histone H3 acetylation levels in the CAPZA1 proximal promoter region were measured by using chromatin immunoprecipitation analysis with an antibody against the acetylated histone H3 in human gastric carcinoma cell line (AGS) cells. Results: CD44v9 is expressed in CAPZA1-overexpressing cells in human gastric cancer tissues. CAPZA1 overexpression enhanced expression of β-catenin, which is a transcription factor for CD44, and epithelial splicing regulatory protein 1, which increases alternative splicing of CD44 to generate CD44v9. CAPZA1-overexpressing cells after cytotoxin-associated gene A accumulation showed CD44v9 expression by inducing nuclear accumulation of β-catenin, concomitant with the enhancement of expression of Sal-like protein 4 and Krüppel-like factor 5, which encode reprogramming factors. Oxidative stress increased the CAPZA1 expression in AGS cells through the enhancement of histone H3 acetylation of CAPZA1 promoter. CAPZA1 expression was increased depending on oxidative stress in H pylori–infected gastric mucosa. Conclusions: CD44v9 expression is evoked from CAPZA1-overexpressing cells after accumulation of cytotoxin-associated gene A. Our findings provide important insights into the mechanisms underlying the development of CD44v9-positive cells.

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Vasodilator oxyfedrine inhibits aldehyde metabolism and thereby sensitizes cancer cells to xCT-targeted therapy

Otsuki Y., Yamasaki J., Suina K., Okazaki S., Koike N., Saya H., Nagano O.

Cancer Science （Cancer Science） 111 （ 1 ） 127 - 136 2019年

ISSN 13479032

© 2019 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association. The major cellular antioxidant glutathione (GSH) protects cancer cells from oxidative damage that can lead to the induction of ferroptosis, an iron-dependent form of cell death triggered by the aberrant accumulation of lipid peroxides. Inhibitors of the cystine-glutamate antiporter subunit xCT, which mediates the uptake of extracellular cystine and thereby promotes GSH synthesis, are thus potential anticancer agents. However, the efficacy of xCT-targeted therapy has been found to be diminished by metabolic reprogramming that affects redox status in cancer cells. Identification of drugs for combination with xCT inhibitors that are able to overcome resistance to xCT-targeted therapy might thus provide the basis for effective cancer treatment. We have now identified the vasodilator oxyfedrine (OXY) as a sensitizer of cancer cells to GSH-depleting agents including the xCT inhibitor sulfasalazine (SSZ). Oxyfedrine contains a structural motif required for covalent inhibition of aldehyde dehydrogenase (ALDH) enzymes, and combined treatment with OXY and SSZ was found to induce accumulation of the cytotoxic aldehyde 4-hydroxynonenal and cell death in SSZ-resistant cancer cells both in vitro and in vivo. Microarray analysis of tumor xenograft tissue showed cyclooxygenase-2 expression as a potential biomarker for the efficacy of such combination therapy. Furthermore, OXY-mediated ALDH inhibition was found to sensitize cancer cells to GSH depletion induced by radiation therapy in vitro. Our findings thus establish a rationale for repurposing of OXY as a sensitizing drug for cancer treatment with agents that induce GSH depletion.

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CD44 variant inhibits insulin secretion in pancreatic β cells by attenuating LAT1-mediated amino acid uptake

Kobayashi N., Okazaki S., Sampetrean O., Irie J., Itoh H., Saya H.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

ISSN 2045-2322

© 2018 The Author(s). CD44 variant (CD44v) contributes to cancer stemness by stabilizing the xCT subunit of system xc(-) and thereby promoting its glutamate-cystine antiporter activity. CD44 has also been implicated in autoimmune insulitis and inflammation in diabetic islets, but whether CD44v regulates insulin secretion has remained unclear. Here we show that CD44v inhibits insulin secretion by attenuating amino acid transport mediated by the L-type amino acid transporter LAT1. CD44v expression level was inversely related to insulin content in islets of normal and diabetic model mice. Knockdown of CD44 increased insulin secretion, the intracellular insulin level, and the transport of neutral amino acids mediated by LAT1 in Min6 cells. Attenuation of the uptake of neutral amino acids with a LAT inhibitor reduced insulin secretion and insulin content in Min6 cells, whereas overexpression of LAT1 increased insulin secretion. Moreover, inhibition of LAT1 prevented the increase in insulin secretion and content induced by CD44 depletion in Min6 cells. Our results thus implicate CD44v in the regulation of insulin secretion and reveal that amino acid transport is rate limiting for such secretion. They further suggest that amino acid transport mediated by LAT1 is a potential therapeutic target for diabetes.

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Gold-nanofève surface-enhanced Raman spectroscopy visualizes hypotaurine as a robust anti-oxidant consumed in cancer survival

Shiota M., Naya M., Yamamoto T., Hishiki T., Tani T., Takahashi H., Kubo A., Koike D., Itoh M., Ohmura M., Kabe Y., Sugiura Y., Hiraoka N., Morikawa T., Takubo K., Suina K., Nagashima H., Sampetrean O., Nagano O., Saya H., Yamazoe S., Watanabe H., Suematsu M.

Nature Communications （Nature Communications） 9 （ 1 ） 2018年12月

ISSN 2041-1723

© 2018 The Author(s). Gold deposition with diagonal angle towards boehmite-based nanostructure creates random arrays of horse-bean-shaped nanostructures named gold-nanofève (GNF). GNF generates many electromagnetic hotspots as surface-enhanced Raman spectroscopy (SERS) excitation sources, and enables large-area visualization of molecular vibration fingerprints of metabolites in human cancer xenografts in livers of immunodeficient mice with sufficient sensitivity and uniformity. Differential screening of GNF-SERS signals in tumours and those in parenchyma demarcated tumour boundaries in liver tissues. Furthermore, GNF-SERS combined with quantum chemical calculation identified cysteine-derived glutathione and hypotaurine (HT) as tumour-dominant and parenchyma-dominant metabolites, respectively. CD44 knockdown in cancer diminished glutathione, but not HT in tumours. Mechanisms whereby tumours sustained HT under CD44-knockdown conditions include upregulation of PHGDH, PSAT1 and PSPH that drove glycolysis-dependent activation of serine/glycine-cleavage systems to provide one-methyl group for HT synthesis. HT was rapidly converted into taurine in cancer cells, suggesting that HT is a robust anti-oxidant for their survival under glutathione-suppressed conditions.

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Tranilast inhibits the expression of genes related to epithelial-mesenchymal transition and angiogenesis in neurofibromin-deficient cells

Harigai R., Sakai S., Nobusue H., Hirose C., Sampetrean O., Minami N., Hata Y., Kasama T., Hirose T., Takenouchi T., Kosaki K., Kishi K., Saya H., Arima Y.

Scientific Reports （Scientific Reports） 8 （ 1 ） 2018年12月

ISSN 2045-2322

© 2018 The Author(s). Neurofibromatosis type 1 (NF1) is caused by germline mutations in the NF1 gene and is characterized by café au lait spots and benign tumours known as neurofibromas. NF1 encodes the tumour suppressor protein neurofibromin, which negatively regulates the small GTPase Ras, with the constitutive activation of Ras signalling resulting from NF1 mutations being thought to underlie neurofibroma development. We previously showed that knockdown of neurofibromin triggers epithelial-mesenchymal transition (EMT) signalling and that such signalling is activated in NF1-associated neurofibromas. With the use of a cell-based drug screening assay, we have now identified the antiallergy drug tranilast (N-(3,4-dimethoxycinnamoyl) anthranilic acid) as an inhibitor of EMT and found that it attenuated the expression of mesenchymal markers and angiogenesis-related genes in NF1-mutated sNF96.2 cells and in neurofibroma cells from NF1 patients. Tranilast also suppressed the proliferation of neurofibromin-deficient cells in vitro more effectively than it did that of intact cells. In addition, tranilast inhibited sNF96.2 cell migration and proliferation in vivo. Knockdown of type III collagen (COL3A1) also suppressed the proliferation of neurofibroma cells, whereas expression of COL3A1 and SOX2 was increased in tranilast-resistant cells, suggesting that COL3A1 and the transcription factor SOX2 might contribute to the development of tranilast resistance.

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Epidermal growth factor receptor promotes glioma progression by regulating xCT and GluN2B-containing N-methyl-d-aspartate–sensitive glutamate receptor signaling

Suina K., Tsuchihashi K., Yamasaki J., Kamenori S., Shintani S., Hirata Y., Okazaki S., Sampetrean O., Baba E., Akashi K., Mitsuishi Y., Takahashi F., Takahashi K., Saya H., Nagano O.

Cancer Science （Cancer Science） 109 （ 12 ） 3874 - 3882 2018年12月

ISSN 13479032

© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association. Autocrine and paracrine factors, including glutamate and epidermal growth factor (EGF), are potent inducers of brain tumor cell invasion, a pathological hallmark of malignant gliomas. System xc(–) consists of xCT and CD98hc subunits and functions as a plasma membrane antiporter for the uptake of extracellular cystine in exchange for intracellular glutamate. We previously showed that the EGF receptor (EGFR) interacts with xCT and thereby promotes the activity of system xc(–) in a kinase-independent manner, resulting in enhanced glutamate release in glioma cells. However, the molecular mechanism underlying EGFR-mediated glioma progression in a glutamate-rich microenvironment has remained unclear. Here we show that the GluN2B subunit of the N-methyl-d-aspartate–sensitive glutamate receptor (NMDAR) is a substrate of EGFR in glioma cells. In response to EGF stimulation, EGFR phosphorylated the COOH-terminal domain of GluN2B and thereby enhanced glutamate-NMDAR signaling and consequent cell migration in EGFR-overexpressing glioma cells. Treatment with the NMDAR inhibitor MK-801 or the system xc(–) inhibitor sulfasalazine suppressed EGF-elicited glioma cell migration. The administration of sulfasalazine and MK-801 also synergistically suppressed the growth of subcutaneous tumors formed by EGFR-overexpressing glioma cells. Furthermore, shRNA-mediated knockdown of xCT and GluN2B cooperatively prolonged the survival of mice injected intracerebrally with such glioma cells. Our findings thus establish a central role for EGFR in the signaling crosstalk between xCT and GluN2B-containing NMDAR in glioma cells.

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T-type Calcium Channels Determine the Vulnerability of Dopaminergic Neurons to Mitochondrial Stress in Familial Parkinson Disease

Tabata Y., Imaizumi Y., Sugawara M., Andoh-Noda T., Banno S., Chai M., Sone T., Yamazaki K., Ito M., Tsukahara K., Saya H., Hattori N., Kohyama J., Okano H.

Stem Cell Reports （Stem Cell Reports） 11 （ 5 ） 1171 - 1184 2018年11月

ISSN 22136711

© 2018 The Author(s) Parkinson disease (PD) is a progressive neurological disease caused by selective degeneration of dopaminergic (DA) neurons in the substantia nigra. Although most cases of PD are sporadic cases, familial PD provides a versatile research model for basic mechanistic insights into the pathogenesis of PD. In this study, we generated DA neurons from PARK2 patient-specific, isogenic PARK2 null and PARK6 patient-specific induced pluripotent stem cells and found that these neurons exhibited more apoptosis and greater susceptibility to rotenone-induced mitochondrial stress. From phenotypic screening with an FDA-approved drug library, one voltage-gated calcium channel antagonist, benidipine, was found to suppress rotenone-induced apoptosis. Furthermore, we demonstrated the dysregulation of calcium homeostasis and increased susceptibility to rotenone-induced stress in PD, which is prevented by T-type calcium channel knockdown or antagonists. These findings suggest that calcium homeostasis in DA neurons might be a useful target for developing new drugs for PD patients. Our study demonstrate the dysregulation of calcium homeostasis and increased susceptibility to rotenone-induced stress in PD patient-derived DA neurons, which are further prevented by T-type calcium channel antagonists. These findings suggest that calcium homeostasis in DA neurons would be a useful target for developing new drugs for PD patients.

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Inhibiting xCT improves 5-fluorouracil resistance of gastric cancer induced by CD44 variant 9 expression

Miyoshi S., Tsugawa H., Matsuzaki J., Hirata K., Mori H., Saya H., Kanai T., Suzuki H.

Anticancer Research （Anticancer Research） 38 （ 11 ） 6163 - 6170 2018年11月

ISSN 02507005

© 2018 International Institute of Anticancer Research.All right reserved. Background/Aim: Cancer stem cells (CSCs) play a critical role in resistance to chemotherapy. CD44 is a cell surface marker of CSCs. CD44 variant 9 (CD44v9) interacts with a cystine-glutamate antiporter (xCT) and is an unfavorable predictive factor in gastric cancer. We investigated the impact of CD44v9 expression on 5-fluorouracil (5-FU) resistance and the efficacy of the xCT inhibitor, sulfasalazine (SASP), in improving drug resistance. Materials and Methods: The human gastric cancer cell line MKN28 was transfected with pRc/CMV plasmids encoding human CD44 or CD44v9, which were used for in vitro and in vivo experiments. Results: CD44v9 expression results in 5-FU resistance by increasing intracellular glutathione and suppressing the drug-induced production of reactive oxygen species (ROS). SASP improved the drug sensitivity of CD44v9-expressing cells. Conclusion: Inhibition of xCT improved the clinical efficacy of chemotherapy against gastric cancer. CD44v9 expression can be a novel biomarker to predict resistance against 5-FU in gastric cancer.

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Modeling sporadic ALS in iPSC-derived motor neurons identifies a potential therapeutic agent

Fujimori K., Ishikawa M., Otomo A., Atsuta N., Nakamura R., Akiyama T., Hadano S., Aoki M., Saya H., Sobue G., Okano H.

Nature Medicine （Nature Medicine） 24 （ 10 ） 1579 - 1589 2018年10月

ISSN 10788956

© 2018, The Author(s). Amyotrophic lateral sclerosis (ALS) is a heterogeneous motor neuron disease for which no effective treatment is available, despite decades of research into SOD1-mutant familial ALS (FALS). The majority of ALS patients have no familial history, making the modeling of sporadic ALS (SALS) essential to the development of ALS therapeutics. However, as mutations underlying ALS pathogenesis have not yet been identified, it remains difficult to establish useful models of SALS. Using induced pluripotent stem cell (iPSC) technology to generate stem and differentiated cells retaining the patients’ full genetic information, we have established a large number of in vitro cellular models of SALS. These models showed phenotypic differences in their pattern of neuronal degeneration, types of abnormal protein aggregates, cell death mechanisms, and onset and progression of these phenotypes in vitro among cases. We therefore developed a system for case clustering capable of subdividing these heterogeneous SALS models by their in vitro characteristics. We further evaluated multiple-phenotype rescue of these subclassified SALS models using agents selected from non-SOD1 FALS models, and identified ropinirole as a potential therapeutic candidate. Integration of the datasets acquired in this study permitted the visualization of molecular pathologies shared across a wide range of SALS models.

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Therapeutic potential of tranilast for the treatment of chronic graft-versus-host disease in mice

Mukai S., Ogawa Y., Saya H., Kawakami Y., Tsubota K.

PLoS ONE （PLoS ONE） 13 （ 10 ） 2018年10月

© 2018 Mukai et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Chronic graft-versus-host disease (cGVHD) is a marked complication of hematopoietic stem cell transplantation, and multiple organs can be affected by cGVHD-induced inflammation and fibrosis. In clinical settings, immunosuppressive agents have been the last resort to treat cGVHD. However, it has been only partially effective for cGVHD. Hence, efficacious treatment of cGVHD is eagerly awaited. Our previous work suggested that oxidative stress was elevated in cGVHD-disordered lacrimal glands and that epithelial-To-mesenchymal transition (EMT) was implicated in fibrosis caused by ocular cGVHD. In addition, our recent article demonstrated that thioredoxin interaction protein (TXNIP) and transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were associated with the development of cGVHD. After our search for effective drugs, we chose tranilast to combat systemic cGVHD. Tranilast is known to (1) act as an inhibitor of the inflammatory molecules TXNIP and NF-κB and (2) exert anti-fibrotic, anti-EMT and anti-oxidative effects. To investigate the effectiveness of tranilast for cGVHD, we used an MHC-compatible, multiple minor histocompatibility antigen-mismatched murine model of cGVHD. Tranilast or a solvent-vehicle were orally given to the allogeneic bone marrow transplantation (allo-BMT) recipients from the day before allo-BMT (Day-1) to Day 27 after allo-BMT. Their cGVHD-vulnerable organs were collected Day 28 after allo-BMT and analyzed by using various methods such as histology, immunohistochemistry and immunoblotting. As indicated by our results, tranilast alleviated cGVHD-elicited inflammation and fibrosis by suppressing the expression and/or activation of TXNIP and NF-κB and preventing EMT. Taken together, although this strategy may not be a complete cure for cGVHD, tranilast could be a promising medication to ameliorate cGVHD-Triggered disabling symptoms.

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Synthetic lethality of the ALDH3A1 inhibitor dyclonine and xCT inhibitors in glutathione deficiency-resistant cancer cells

Okazaki S., Shintani S., Hirata Y., Suina K., Semba T., Yamasaki J., Umene K., Ishikawa M., Saya H., Nagano O.

Oncotarget （Oncotarget） 9 （ 73 ） 33832 - 33843 2018年09月

© Okazaki et al. The cystine-glutamate antiporter subunit xCT suppresses iron-dependent oxidative cell death (ferroptosis) and is therefore a promising target for cancer treatment. Given that cancer cells often show resistance to xCT inhibition resulting in glutathione (GSH) deficiency, however, we here performed a synthetic lethal screen of a drug library to identify agents that sensitize the GSH deficiency-resistant cancer cells to the xCT inhibitor sulfasalazine. This screen identified the oral anesthetic dyclonine which has been recently reported to act as a covalent inhibitor for aldehyde dehydrogenases (ALDHs). Treatment with dyclonine induced intracellular accumulation of the toxic aldehyde 4-hydroxynonenal in a cooperative manner with sulfasalazine. Sulfasalazine-resistant head and neck squamous cell carcinoma (HNSCC) cells were found to highly express ALDH3A1 and knockdown of ALDH3A1 rendered these cells sensitive to sulfasalazine. The combination of dyclonine and sulfasalazine cooperatively suppressed the growth of highly ALDH3A1-expressing HNSCC or gastric tumors that were resistant to sulfasalazine monotherapy. Our findings establish a rationale for application of dyclonine as a sensitizer to xCT-targeted cancer therapy.

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HER2 heterogeneity is associated with poor survival in HER2-positive breast cancer

Hosonaga M., Arima Y., Sampetrean O., Komura D., Koya I., Sasaki T., Sato E., Okano H., Kudoh J., Ishikawa S., Saya H., Ishikawa T.

International Journal of Molecular Sciences （International Journal of Molecular Sciences） 19 （ 8 ） 2018年08月

ISSN 1661-6596

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity has been reported in 16–36% of HER2-positive breast cancer and its clinical impact is under discussion. We examined the biological effects of HER2-heterogeneity on mouse models and analyzed metastatic brains by RNA sequence analysis. A metastatic mouse model was developed using 231-Luc (triple negative cells) and 2 HER2-positive cell lines, namely, HER2-60 and HER2-90 which showed heterogeneous and monotonous HER2 expressions, respectively. Metastatic lesions developed in 3 weeks in all the mice injected with HER2-60 cells, and in 69% of the mice injected with HER2-90 and 87.5% of the mice injected with 231-Luc. The median survival days of mice injected with 231-Luc, HER2-60, and HER2-90 cells were 29 (n = 24), 24 (n = 22) and 30 (n = 13) days, respectively. RNA sequence analysis showed that CASP-1 and its related genes were significantly downregulated in metastatic brain tumors with HER2-60 cells. The low expression of caspase-1 could be a new prognostic biomarker for early relapse in HER2-positive breast cancer.

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Development of a functional thyroid model based on an organoid culture system

Saito Y., Onishi N., Takami H., Seishima R., Inoue H., Hirata Y., Kameyama K., Tsuchihashi K., Sugihara E., Uchino S., Ito K., Kawakubo H., Takeuchi H., Kitagawa Y., Saya H., Nagano O.

Biochemical and Biophysical Research Communications （Biochemical and Biophysical Research Communications） 497 （ 2 ） 783 - 789 2018年03月

ISSN 0006-291X

© 2018 Elsevier Inc. The low turnover rate of thyroid follicular cells and the lack of a long-term thyroid cell culture system have hampered studies of thyroid carcinogenesis. We have now established a thyroid organoid culture system that supports thyroid cell proliferation in vitro. The established mouse thyroid organoids performed thyroid functions including thyroglobulin synthesis, iodide uptake, and the production and release of thyroid hormone. Furthermore, transplantation of the organoids into recipient mice resulted in the formation of normal thyroid–like tissue capable of iodide uptake and thyroglobulin production in vivo. Finally, forced expression of oncogenic NRAS (NRASQ61R) in thyroid organoids established from p53 knockout mice and transplantation of the manipulated organoids into mouse recipients generated a model of poorly differentiated thyroid cancer. Our findings suggest that this newly developed thyroid organoid culture system is a potential research tool for the study of thyroid physiology and pathology including thyroid cancer.

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Prospects for new lung cancer treatments that target EMT signaling

Otsuki Y., Saya H., Arima Y.

Developmental Dynamics （Developmental Dynamics） 247 （ 3 ） 462 - 472 2018年03月

ISSN 1058-8388

© 2017 Wiley Periodicals, Inc. Lung cancer is the most common cancer worldwide. Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, molecularly targeted therapy including epidermal growth factor receptor or anaplastic lymphoma kinase inhibitors, and immunotherapy. These treatments can be administered alone or in combination. Despite therapeutic advances, however, lung cancer remains the leading cause of cancer death. Recent studies have indicated that epithelial-mesenchymal transition (EMT) is associated with malignancy in various types of cancer, and activation of EMT signaling in cancer cells is widely considered to contribute to metastasis, recurrence, or therapeutic resistance. In this review, we provide an overview of the role of EMT in the progression of lung cancer. We also discuss the prospects for new therapeutic strategies that target EMT signaling in lung cancer. Developmental Dynamics 247:462–472, 2018. © 2017 Wiley Periodicals, Inc.

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Metabolic heterogeneity and plasticity of glioma stem cells in a mouse glioblastoma model

Shibao S., Minami N., Koike N., Fukui N., Yoshida K., Saya H., Sampetrean O.

Neuro-Oncology （Neuro-Oncology） 20 （ 3 ） 343 - 354 2018年02月

ISSN 1522-8517

© 2018 The Author(s). Background. Glioblastomas have been shown to rely on glycolysis as an energy source. However, recent evidence suggests that at least a subset of glioma cells with stem cell-like properties can thrive on oxidative phosphorylation. It remains unclear whether both metabolic phenotypes support tumor propagation, if they are independent, and how stable they are. The present study investigated these questions with the use of isogenic murine glioma stem cells (GSCs). Methods. GSCs were established from tumors formed by Ink4a/Arf-null, H-RasV12-expressing glioma-initiating cells that differed in extracellular acidification potential. Metabolic characteristics of GSCs were determined by measurement of glucose, oxygen, and glutamine uptake, ATP content, and lactate production. Effects of metabolic inhibitors and changes in oxygen or nutrient availability on lactate production and tumorsphere growth were also determined. Results. GSCs were found either to consume more glucose and produce more lactate or to consume more oxygen and maintain a higher ATP content depending on the metabolic characteristics of the tumor cells of origin. The latter, mitochondrial-type GSCs increased lactate production after treatment with the oxidative phosphorylation inhibitor oligomycin or phenformin. Exposure to hypoxia also increased lactate production and expression of glycolysis-related enzymes and metabolites in mitochondrial-type GSCs in a reversible manner. Conclusions. Both glycolytic and mitochondrial-type energy production can sustain tumor propagation by isogenic GSCs. Whereas both phenotypes can be independent and stable, cells that rely on oxidative phosphorylation can also switch to a more glycolytic phenotype in response to metabolic stress, suggesting that plasticity is a further characteristic of GSC metabolism.

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Recurrent Spindle Cell Carcinoma Shows Features of Mesenchymal Stem Cells

Ouchi T., Morikawa S., Shibata S., Takahashi M., Yoshikawa M., Soma T., Miyashita H., Muraoka W., Kameyama K., Kawana H., Arima Y., Saya H., Okano H., Nakagawa T., Asoda S.

Journal of Dental Research （Journal of Dental Research） 97 （ 7 ） 779 - 786 2018年02月

ISSN 0022-0345

© 2018, International & American Associations for Dental Research. This study investigated a case of spindle cell carcinoma (SpCC) in tongue pathological lesions. The patient experienced a local recurrence and distant metastasis after surgical intervention. Although standard chemotherapy was administered, a granulomatous mass continued to develop. This aggressive growth led to survival of the tumor. Secondary debulking surgery was performed to improve the patient’s quality of life at the request of the patient. Using a tissue sample derived from the secondary debulking surgery, we performed an analysis of the tumor’s cell surface antigens, differentiation potential, metastatic ability, and inhibition potential by anticancer reagents. In vitro analysis revealed that the cell population grown under adherent culture conditions expressed the mesenchymal stem cell (MSC) markers CD73, CD90, and CD105. The cell line established from this SpCC contained colony-forming unit fibroblasts (CFU-Fs) and exhibited multipotent differentiation into several mesenchymal lineages, including bone, cartilage, and fat. The SpCC cells also displayed vigorous mobilization. These characteristics suggested that they had the differentiation potential of mesenchymal cells, especially MSCs, rather than that of epithelial cells. The surgical specimen analyzed in this study resisted the molecular target reagent cetuximab, which is an epidermal growth factor receptor inhibitor. This clinical insight revealed that chemotherapy-resistant SpCC cells have different characteristics compared to most other cancer cells, which are sensitive to cetuximab. Our cell death assay revealed that SpCC cell death was induced by the anticancer drug imatinib, which is known to inhibit protein tyrosine kinase activity of ABL, platelet-derived growth factor receptor α (PDGFRα), and KIT. Here, we report recurrent SpCC with characteristics of MSCs and potential for treatment with imatinib.

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Variant isoforms of CD44 involves acquisition of chemoresistance to cisplatin and has potential as a novel indicator for identifying a cisplatin-resistant population in urothelial cancer

Hagiwara M., Kikuchi E., Tanaka N., Kosaka T., Mikami S., Saya H., Oya M.

BMC Cancer （BMC Cancer） 18 （ 1 ） 2018年01月

ISSN 1471-2407

© 2018 The Author(s). Background: Cisplatin is the most commonly used chemotherapeutic agent in the treatment of patients with metastatic and/or recurrent urothelial cancer. However, the effectiveness of these treatments is severely limited due to the development of cisplatin resistance. Cancer stem cells have been documented as one of the key hypotheses involved in chemoresistance. CD44v8-10 has been identified as one of the new cancer stem cells markers and was recently shown to enhance the antioxidant system by interaction with xCT, a subunit of the cystine transporter modulating intracellular glutathione synthesis. The aim of the present study was to investigate the clinical role of CD44v8-10 and the molecular mechanism underlying the acquisition of cisplatin resistance through CD44v8-10 in urothelial cancer. Methods: We analyzed the clinical significance of the immunohistochemical CD44v9 expression, which detects the immunogen of human CD44v8-10, in 77 urothelial cancer patients treated with cisplatin-based systemic chemotherapy for recurrence and/or metastasis. We then evaluated the biological role of CD44v8-10 in the acquisition of cisplatin resistance using the urothelial cancer cell lines, T24 and T24PR, which were generated to acquire resistance to cisplatin. Results: The 5-year cancer-specific survival rate was significantly lower in the CD44v9-positive group than in the CD44v9-negative group (P = 0.008). Multivariate analyses revealed that CD44v9 positivity was an independent risk factor of cancer-specific survival (P = 0.024, hazard ratio = 5.16) in urothelial cancer patients who had recurrence and/or metastasis and received cisplatin-based chemotherapy. The expression of CD44v8-10 and xCT was stronger in T24PR cells than in T24 cells. The amount of intracellular glutathione was significantly higher in T24PR cells than in T24 cells (p < 0.001), and intracellular reactive oxygen species production by cisplatin was lower in T24PR cells than in T24 cells. Furthermore, the knockdown of CD44v8-10 by siRNA led to the recovery of cisplatin sensitivity in T24PR cells. Conclusions: CD44v9 in tumor specimens has potential as a novel indicator for identifying a cisplatin-chemoresistant population among urothelial cancer patients. CD44v8-10 contributes to reactive oxygen species defenses, which are involved in chemoresistance, by promoting the function of xCT, which adjusts the synthesis of glutathione.

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Periostin antisense oligonucleotide suppresses bleomycin-induced formation of a lung premetastatic niche for melanoma

Semba T., Sugihara E., Kamoshita N., Ueno S., Fukuda K., Yoshino M., Takao K., Yoshikawa K., Izuhara K., Arima Y., Suzuki M., Saya H.

Cancer Science （Cancer Science） 109 （ 5 ） 1447 - 1454 2018年01月

ISSN 1347-9032

© 2018 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association. Metastasis is the leading cause of cancer death. A tumor-supportive microenvironment, or premetastatic niche, at potential secondary tumor sites plays an important role in metastasis, especially in tumor cell colonization. Although a fibrotic milieu is known to promote tumorigenesis and metastasis, the underlying molecular contributors to this effect have remained unclear. Here we show that periostin, a component of the extracellular matrix that functions in tissue remodeling, has a key role in formation of a fibrotic environment that promotes tumor metastatic colonization. We found that periostin was widely expressed in fibrotic lesions of mice with bleomycin-induced lung fibrosis, and that up-regulation of periostin expression coincided with activation of myofibroblasts positive for α-smooth muscle actin. We established a lung metastasis model for B16 murine melanoma cells and showed that metastatic colonization of the lung by these cells was markedly promoted by bleomycin-induced lung fibrosis. Inhibition of periostin expression by giving an intratracheal antisense oligonucleotide targeting periostin mRNA was found to suppress bleomycin-induced lung fibrosis and thereby to attenuate metastatic colonization of the lung by melanoma cells. Our results indicate that periostin is a key player in the development of bleomycin-induced fibrosis and consequent enhancement of tumor cell colonization in the lung. Our results therefore implicate periostin as a potential target for prevention or treatment of lung metastasis.

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Dynamic changes in CD44v-positive cells after preoperative anti-HER2 therapy and its correlation with pathologic complete response in HER2-positive breast cancer

Yamauchi T., Fernandez J., Imamura C., Yamauchi H., Jinno H., Takahashi M., Kitagawa Y., Nakamura S., Lim B., Krishnamurthy S., Reuben J., Liu D., Tripathy D., Chen H., Takebe N., Saya H., Ueno N.

Oncotarget （Oncotarget） 9 （ 6 ） 6872 - 6882 2018年01月

ISSN 1949-2553

© Yamauchi et al. Chemotherapy has been reported to increase the proportion of cancer stem cells (CSCs) and to promote epithelial-mesenchymal transition (EMT) phenotype changes. Anti-HER2 therapy may provide a strategy for eliminating CSC and EMT, which contribute to therapeutic resistance. No study has determined the changes in the quantity or characteristics of CSCs or circulating tumor cells (CTCs) with EMT phenotype during preoperative anti-HER2 therapy, and whether these changes correlate to response to dual anti-HER2 therapy. In a prospective clinical trial to evaluate pharmacodynamic biomarkers, 18 patients with operable primary HER2-positive breast cancer received dual anti-Her2 preoperative therapy with trastuzumab and lapatinib with paclitaxel. Proportions of tumor cells with CSC characteristics and EMT markers in CTC's were estimated at baseline, after 6 and 18 weeks of preoperative therapy to determine the quantitative cutoff value to predict pathologic complete response (pCR). Out of 18 patients, 8 (44%) had a pCR; 5 of these 8 patients (62%) were positive for CD44v at baseline and none were positive on the 6-week biopsy. In contrast, 6 of the 10 patients without pCR exhibited persistent levels, or enrichment of CD44v proportion and expression at 6 and 18 weeks (p=0.0128). Other biomarkers were not statistically significant predictors of pCR. Enrichment of CD44v-positive tumor cells after dual anti-HER2 therapy alone may predict poor response to dual anti-HER2 therapy plus chemotherapy.

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