Misc - SUZUKI Hiromu

Small interfering RNA-Induced CHFR silencing sensitizes oral squamous cell cancer cells to microtubule inhibitors

K Ogi, M Toyota, H Mita, A Satoh, L Kashima, Y Sasaki, H Suzuki, K Akino, N Nishikawa, M Noguchi, Y Shinomura, K Imai, H Hiratsuka, T Tokino

CANCER BIOLOGY & THERAPY ( LANDES BIOSCIENCE )  4 ( 7 ) 773 - 780  2005.07

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Alterations in the function of cell cycle checkpoints are frequently detected in oral squamous cell carcinomas (OSCCs), and are often associated with the sensitivity of the cancer cells to chemotherapeutic drugs. Recently, a mitotic checkpoint gene, Chfr, was shown to be inactivated by promoter methylation and point mutations in various human tumors. Here we show that the absence of its product, CHFR, is associated with mitotic checkpoint dysfunction, and that cancer cells lacking CHFR are sensitive to microtubule inhibitors. Checkpoint impairment appears to be caused by a prophase defect in this case, as OSCC cells lacking CHFR showed phosphorylation of histone H3 on Ser10 and translocation of cyclin B1 to the nucleus. When CHFR-deficient OSCC cells were treated with a microtubule inhibitor (docetaxel or paclitaxel), significant numbers of apoptotic cells were observed. Moreover, disruption of CHFR using small interfering RNA (siRNA) impaired the mitotic checkpoint, thereby reducing the ability of OSCC cells to arrest at G(2)/M phase and making them more sensitive to microtubule inhibitors. Our results suggest that CHFR could be a useful molecular target for chemotherapy.

Upregulation of BNIP3 by 5-aza-2 '-deoxycytidine sensitizes pancreatic cancer cells to hypoxia-mediated cell death

T Abe, M Toyota, H Suzuki, M Murai, K Akino, M Ueno, M Nojima, A Yawata, H Miyakawa, T Suga, H Ito, T Endo, T Tokino, Y Hinoda, K Imai

JOURNAL OF GASTROENTEROLOGY ( SPRINGER TOKYO )  40 ( 5 ) 504 - 510  2005.05

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Background. Pancreatic cancer cells often show resistance to hypoxia-mediated apoptosis, but the molecular mechanism underlying that resistance remains unknown. The purpose of the present study, therefore, was to examine the role of epigenetic gene alteration in the resistance to hypoxia-mediated apoptosis among pancreatic cancer cells. Methods. Reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the expression of five genes associated with hypoxia-mediated apoptosis (PUMA, Caspase-8 [CASP8], APAF-1, BNIP3, and BNIP3L) in a panel of pancreatic cancer cell lines. Protein expression was examined by Western blot analysis, using lysates from cells incubated under normoxic or hypoxic conditions. The methylation status of the genes was determined using bisulfite-PCR and sequencing. The percentages of cells that were apoptotic were determined using flow cytometry. Results. Under normoxic conditions, the expression of the BNIP-3 gene varied among the 12 pancreatic cancer cell lines tested, with 50% of them showing no BNIP3 expression at all, whereas expression of the other four genes was readily detected in all 12 cell lines. DNA methylation of BNIP-3's CpG island in the region around the transcription start site of the gene was closely associated with its silencing. The expression of BNIP3 was restored by the methyltransferase inhibitor 5-aza-deoxycytidine (5-aza-dC), as was the hypoxia-mediated pancreatic cancer cell death. Conclusions. BNIP3 expression is silenced in some pancreatic cancer cells by the methylation of its CpG island. Demethylation of BNIP3, using a methyltransferase inhibitor, restores the gene's expression and induces hypoxia-mediated cell death. BNIP-3 may thus be a useful target for new therapies aimed at treating pancreatic cancer.

DOI PubMed CiNii

現代医学の焦点(269)新しい大腸癌抑制遺伝子--SFRP

鈴木 拓, 豊田 実, 野島 正寛

日本臨床 ( 日本臨床社 )  63 ( 4 ) 707 - 719  2005.04

CiNii

Aberrant DNA methylation associated with silencing BNIP3 gene expression in haematopoietic tumours

M Murai, M Toyota, A Satoh, H Suzuki, K Akino, H Mita, Y Sasaki, T Ishida, L Shen, G Garcia-Manero, JPJ Issa, Y Hinoda, T Tokino, K Imai

BRITISH JOURNAL OF CANCER ( NATURE PUBLISHING GROUP )  92 ( 6 ) 1165 - 1172  2005.03

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Hypoxia is a key factor contributing to the progression of human neoplasias and to the development of resistance to chemotherapy. BNIP3 is a proapoptotic member of the Bcl-2 protein family involved in hypoxia-induced cell death. We evaluated the expression and methylation status of BNIP3 gene to better understand the role of epigenetic alteration of its expression in haematopoietic tumours. Methylation of the region around the BNIP3 transcription start site was detected in four acute lymphocytic leukaemia, one multiple myeloma and one Burkitt lymphoma cell lines, and was closely associated with silencing the gene. That expression of BNIP3 was restored by treatment with 5-aza2 '-deoxycytidine (5-aza-dC), a methyltransferase inhibitor, which confirmed the gene to be epigenetically inactivated by methylation. Notably, re-expression of BNIP3 using 5-aza2-dC also restored hypoxia-mediated cell death in methylated cell lines. Acetylation of histone H3 in the 5 ' region of the gene, which was assessed using chromatin immunoprecipitation assays, correlated directly with gene expression and inversely with DNA methylation. Among primary tumours, methylation of BNIP3 was detected in five of 34 (15%) acute lymphocytic leukaemias, six of 35 (17%) acute myelogenous leukaemias and three of 14 (21%) multiple myelomas. These results suggest that aberrant DNA methylation of the 5 ' CpG island and histone deacetylation play key roles in silencing BNIP3 expression in haematopoietic tumours.

DOI

胃癌においてメチル化により不活化している新規癌抑制遺伝子の同定

上野理子, 豊田実, 豊田実, 鈴木拓, 鈴木拓, 秋野公臣, 秋野公臣, 見田裕章, 見田裕章, 佐々木泰史, 佐々木泰史, 篠村恭久, 時野隆至, 今井浩三

日本癌学会学術総会記事   64th  2005

J-GLOBAL

分裂期チェックポイント分子CHFRの機能解析

鹿島理沙, 見田裕章, 豊田実, 豊田実, 豊田実, 佐々木泰史, 井戸川雅史, 井戸川雅史, 鈴木拓, 秋野公臣, 秋野公臣, 時野隆至

日本分子生物学会年会講演要旨集   28th  2005

J-GLOBAL

口腔へん平上皮癌における分泌型Frizzled関連蛋白遺伝子のエピジェネティックな不活化

曽我部陽平, 曽我部陽平, 鈴木拓, 鈴木拓, 鈴木拓, 豊田実, 豊田実, 豊田実, 秋野公臣, 秋野公臣, 佐々木泰史, 見田裕章, 草野真暢, 草野真暢, 今井崇, 時野隆至, 平塚博義

日本癌学会学術総会記事   64th  2005

J-GLOBAL

RASシグナル伝達におけるRASSF2遺伝子の機能解析

高橋文彦, 豊田実, 豊田実, 秋野公臣, 秋野公臣, 鈴木拓, 鈴木拓, 見田裕章, 佐々木泰史, 篠村恭久, 今井浩三, 時野隆至

日本癌学会学術総会記事   64th  2005

J-GLOBAL

分裂期チェックポイントCHFRの機能解析

鹿島理沙, 見田裕章, 豊田実, 豊田実, 豊田実, 佐々木泰史, 鈴木拓, 鈴木拓, 秋野公臣, 秋野公臣, 時野隆至

日本癌学会学術総会記事   64th  2005

J-GLOBAL

CpG Island Methylator Phenotype胃癌の分子生物・臨床病理学的特徴とEBウイルス関連胃癌との関係

草野真暢, 草野真暢, 豊田実, 豊田実, 鈴木拓, 鈴木拓, 秋野公臣, 秋野公臣, 見田裕章, 佐々木泰史, 垣内英樹, 伊東文生, 篠村恭久, 今井浩三, 時野隆至

日本癌学会学術総会記事   64th  2005

J-GLOBAL

胃癌におけるメチル化標的新規癌関連遺伝子の検討

渡辺嘉行, 渡辺嘉行, 豊田実, 豊田実, 秋野公臣, 秋野公臣, 鈴木拓, 鈴木拓, 井戸川雅史, 井戸川雅史, 鹿島里沙, 見田裕章, 佐々木泰史, 伊東文生, 時野隆至

日本分子生物学会年会講演要旨集   28th  2005

J-GLOBAL

胃癌において異常メチル化により不活化している新規遺伝子ACMG1

佐藤裕信, 豊田実, 豊田実, 鈴木拓, 鈴木拓, 秋野公臣, 秋野公臣, 見田裕章, 佐々木泰史, 上野理子, 篠村恭久, 篠村恭久, 時野隆至, 今井浩三

日本癌学会学術総会記事   64th  2005

J-GLOBAL

p53によるVDR(vitamin D receptor)の発現誘導

丸山玲緒, 豊田実, 豊田実, 明石浩史, 明石浩史, 佐々木泰史, 青木文夫, 見田裕章, 鈴木拓, 鈴木拓, 篠村恭久, 今井浩三, 時野隆至

日本癌学会学術総会記事   64th  2005

J-GLOBAL

塩基配列情報を基盤とした定量的ゲノム解析法の開発と癌研究への応用

見田裕章, 豊田実, 豊田実, 丸山玲緒, 青木文夫, 明石浩史, 佐々木泰史, 鹿島理沙, 秋野公臣, 鈴木拓, 苗代康司, 井戸川雅史, 大西浩文, 大西浩文, 辰巳治之, 今井浩三, 篠村恭久, 時野隆至

日本分子生物学会年会講演要旨集   28th  2005

J-GLOBAL

5-aza-2’-deoxycytidineによるBNIP3遺伝子の発現回復はすい癌細胞における低酸素誘導性細胞死感受性を増強する

阿部環, 豊田実, 豊田実, 鈴木拓, 鈴木拓, 秋野公臣, 秋野公臣, 見田裕章, 見田裕章, 佐々木泰史, 佐々木泰史, 遠藤高夫, 篠村恭久, 時野隆至, 今井浩三

日本癌学会学術総会記事   64th  2005

J-GLOBAL

p53によるビタミンD受容体の発現誘導と抗腫よう効果の増強作用

丸山玲緒, 豊田実, 豊田実, 佐々木泰史, 青木文夫, 明石浩史, 明石浩史, 見田裕章, 鈴木拓, 鈴木拓, 今井浩三, 篠村恭久, 時野隆至

日本分子生物学会年会講演要旨集   28th  2005

J-GLOBAL

SFRP, a family of new colorectal tumor suppressor candidate genes

Hiromu Suzuki, Minoru Toyota, Masanori Nojima, Mitsuru Mori, Kohzoh Imai

Nippon rinsho. Japanese journal of clinical medicine   63 ( 4 ) 707 - 719  2005

Book review, literature introduction, etc.  

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Aberrant Wnt pathway signaling is an early progression event in up to 90% of colorectal cancers (CRC). It occurs mainly through mutations of APC or beta-catenin. We have identified frequent promoter hypermethylation and gene silencing of the secreted frizzled-related protein (SFRP) genes in CRC. SFRPs possess a domain similar to one in the Wnt receptor Frizzled proteins and can inhibit Wnt receptor binding to downregulate pathway signaling in development. We next found that restoration of SFRP function in CRC cells attenuates Wnt signaling even in the presence of downstream mutations. We also show that the epigenetic loss of SFRP function occurs early in CRC progression and may, thus, provide constitutive Wnt signaling which is required to complement downstream mutations in the evolution of CRC.

PubMed

Epigenetic inactivation of class II transactivator (CIITA) is associated with the absence of interferon-gamma-induced HLA-DR expression in colorectal and gastric cancer cells

A Satoh, M Toyota, H Ikeda, Y Morimoto, K Akino, H Mita, H Suzuki, Y Sasaki, T Kanaseki, Y Takamura, H Soejima, T Urano, K Yanagihara, T Endo, Y Hinoda, M Fujita, M Hosokawa, N Sato, T Tokino, K Imai

ONCOGENE ( NATURE PUBLISHING GROUP )  23 ( 55 ) 8876 - 8886  2004.11

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Tightly regulated at the level of transcription, expression of MHC class II molecules varies significantly among gastrointestinal cancers. High levels of MHC class II expression are often associated with a better prognosis, which is indicative of the involvement of CD4(+) lymphocytes in tumor suppression, but the molecular mechanism by which MHC class II expression is regulated remains unclear. In the present study, we investigated the expression of one inducible MHC class II molecule, HLA-DR, and its coactivators in a panel of colorectal and gastric cancer cell lines. Interferon-gamma induced expression of HLA-DR in 14 of 20 cell lines tested; the remaining six cell lines did not express HLA-DR. Analysis of the expression of transcription factors and coactivators associated with HLA-DR revealed that the loss of CIITA expression was closely associated with the absence of HLA-DR induction. Moreover, DNA methylation of the 50 CpG island of CIITA-PIV was detected in all cancer cells that lacked CIITA. The methylation and resultant silencing of CIITA-PIV depended on the activities of two DNA methyltransferases, DNMT1 and DNMT3B, and their genetic inactivation restored CIITA-PIV expression. It thus appears that CIITA methylation is a key mechanism that enables some gastrointestinal cancer cells to escape immune surveillance.

DOI

Mammalian DNA methyltransferase 1 - Inspiration for new directions

AH Ting, KW Jair, H Suzuki, RWC Yen, SB Baylin, KE Schuebel

CELL CYCLE ( TAYLOR & FRANCIS INC )  3 ( 8 ) 1024 - 1026  2004.08

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The role of DNA methyltransferase 1, DNMT1, in human cancer cells has recently been contested. In this setting, DNMT1's function as the sole maintenance methyltransferase was based on the assumption that its biological activity is identical to the mouse homologue. However, the application of recent technological advances, including gene targeting and siRNA mediated ablation studies, has cast doubt on this presumed role. Here, we attempt to shed light on these new data within the context of previous experiments.

CpG island hypermethylation is maintained in human colorectal cancer cells after RNAi-mediated depletion of DNMT1

AH Ting, KW Jair, H Suzuki, RWC Yen, SB Baylin, KE Schuebel

NATURE GENETICS ( NATURE PUBLISHING GROUP )  36 ( 6 ) 582 - 584  2004.06

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The role of the primary mammalian DNA methyltransferase, DNMT1, in maintaining CpG island methylation in human colon cancer cells has recently been questioned. This controversy has arisen from discrepancies between genetic knockout and RNA interference-mediated knockdown studies. Here, we re-examined the RNA interference-based approach and found that hypermethylation of single-copy genes is maintained in cells transiently and stably depleted of DNMT1.

DOI PubMed CiNii