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Tetsuichi Yoshizato, Naoko Watanabe-Okochi,
Yasuhito Nannya,
Motoshi Ichikawa,
Tsuyoshi Takahashi,
Tomohiko Sato,
Akiko Masuda,
Yutaka Yatomi,
Nelson Hirokazu Tsuno,
Mineo Kurokawa,
Koki Takahashi
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ABSTRACT: Allogeneic peripheral blood stem cell transplantation (PBSCT) is an indispensable treatment option for hematological malignancy. The optimal collection day after granulocyte colony-stimulating factor (G-CSF) administration should be determined by peripheral blood pre-apheresis CD34 positive (CD34(+)) cell percentage. However, pre-apheresis CD34(+) cell analysis is not available for most institutions in Japan. Prediction of the optimal collection day based on objective parameters, other than direct CD34(+) cell count, is thus an important matter for investigation. To identify potential predictive factors, clinical parameters in 79 related donors who received allogeneic peripheral blood stem cell (PBSC) collection were analyzed. Eight factors were significantly correlated with the number of CD34(+) cells per donor body weight on the fourth day (day 4) after G-CSF administration in univariate analysis. Using multi-regression analysis, we made a simple scoring system comprising age, sex, LDH on day 4 and RBC count at the baseline, which significantly predicted CD34(+) cell yield (P = 0.048). This system allows us to determine the optimal PBSC collection day. When the score is 0 or 1 on day 4, starting apheresis on day 5 potentially helps avoiding the need for multiple harvests. Score 3 or 4 on day 4 is indicative of better performance if apheresis is started on day 4.
International journal of hematology 05/2013; · 1.17 Impact Factor
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ABSTRACT: Since its discovery from a translocation in leukemias, the runt-related transcription factor 1/acute myelogenous leukemia-1 (RUNX1/AML1), which is widely expressed in hematopoietic cells, has been extensively studied. Many lines of evidence have shown that RUNX1 plays a critical role in regulating the development and precise maintenance of mammalian hematopoiesis. Studies using knockout mice have shown the importance of RUNX1 in a wide variety of hematopoietic cells, including hematopoietic stem cells and megakaryocytes. Recently, target molecular processes of RUNX1 in normal and malignant hematopoiesis have been revealed. Although RUNX1 is not required for the maintenance of hematopoietic stem cells, it is required for the homeostasis of hematopoietic stem and progenitor cells, and expansion of hematopoietic stem and progenitor cells due to RUNX1 deletion may be an important cause of human leukemias. Molecular abnormalities cooperating with loss of RUNX1 have also been identified. These findings may lead to a further understanding of human leukemias, and suggest novel molecular targeted therapies in the near future.
International journal of hematology 04/2013; · 1.17 Impact Factor
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Naoko Watanabe-Okochi,
Akihide Yoshimi,
Tomohiko Sato,
Toshiyuki Ikeda,
Keiki Kumano,
Kazuki Taoka,
Yumiko Satoh,
Akihito Shinohara,
Takako Tsuruta,
Akiko Masuda,
Hiromitsu Yokota,
Yutaka Yatomi,
Koki Takahashi,
Jiro Kitaura,
Toshio Kitamura,
Mineo Kurokawa
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ABSTRACT: Key points The shortest isoform of C/EBPβ, Liver inhibitory protein (LIP), collaborates with Evi1 in leukemogenesis.
Blood 04/2013; · 9.90 Impact Factor
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Toshio Kitamura, Naoko Watanabe-Okochi,
Daichi Inoue,
Katsuhiro Togami,
Tomoyuki Uchida,
Yuuki Kagiyama,
Kimihito Kawabata,
Shigeru Chiba,
Yuka Harada,
Hironori Harada,
Jiro Kitaura,
Fumio Nakahara
[Rinshō ketsueki] The Japanese journal of clinical hematology 08/2012; 53(8):734-9.
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Masahiro Nakagawa,
Munetake Shimabe, Naoko Watanabe-Okochi,
Shunya Arai,
Akihide Yoshimi,
Akihito Shinohara,
Nahoko Nishimoto,
Keisuke Kataoka,
Tomohiko Sato,
Keiki Kumano,
Yasuhito Nannya,
Motoshi Ichikawa,
Yoichi Imai,
Mineo Kurokawa
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ABSTRACT: Functional deregulation of transcription factors has been found in many types of tumors. Transcription factor AML1/RUNX1 is one of the most frequent targets of chromosomal abnormalities in human leukemia and altered function of AML1 is closely associated with malignant transformation of hematopoietic cells. However, the molecular basis and therapeutic targets of AML1-related leukemia are still elusive. Here, we explored immediate target pathways of AML1 by in vitro synchronous inactivation in hematopoietic cells. We found that AML1 inhibits NF-κB signaling through interaction with IκB kinase complex in the cytoplasm. Remarkably, AML1 mutants found in myeloid tumors lack the ability to inhibit NF-κB signaling, and human cases with AML1-related leukemia exhibits distinctly activated NF-κB signaling. Furthermore, inhibition of NF-κB signaling in leukemic cells with mutated AML1 efficiently blocks their growth and development of leukemia. These findings reveal a novel role for AML1 as a cytoplasmic attenuator of NF-κB signaling and indicate that NF-κB signaling is one of the promising therapeutic targets of hematologic malignancies with AML1 abnormality.
Blood 12/2011; 118(25):6626-37. · 9.90 Impact Factor
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Akihide Yoshimi,
Susumu Goyama, Naoko Watanabe-Okochi,
Yumiko Yoshiki,
Yasuhito Nannya,
Eriko Nitta,
Shunya Arai,
Tomohiko Sato,
Munetake Shimabe,
Masahiro Nakagawa,
Yoichi Imai,
Toshio Kitamura,
Mineo Kurokawa
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ABSTRACT: Evi1 (ecotropic viral integration site 1) is essential for proliferation of hematopoietic stem cells and implicated in the development of myeloid disorders. Particularly, high Evi1 expression defines one of the largest clusters in acute myeloid leukemia and is significantly associated with extremely poor prognosis. However, mechanistic basis of Evi1-mediated leukemogenesis has not been fully elucidated. Here, we show that Evi1 directly represses phosphatase and tensin homologue deleted on chromosome 10 (PTEN) transcription in the murine bone marrow, which leads to activation of AKT/mammalian target of rapamycin (mTOR) signaling. In a murine bone marrow transplantation model, Evi1 leukemia showed modestly increased sensitivity to an mTOR inhibitor rapamycin. Furthermore, we found that Evi1 binds to several polycomb group proteins and recruits polycomb repressive complexes for PTEN down-regulation, which shows a novel epigenetic mechanism of AKT/mTOR activation in leukemia. Expression analyses and ChIPassays with human samples indicate that our findings in mice models are recapitulated in human leukemic cells. Dependence of Evi1-expressing leukemic cells on AKT/mTOR signaling provides the first example of targeted therapeutic modalities that suppress the leukemogenic activity of Evi1. The PTEN/AKT/mTOR signaling pathway and the Evi1-polycomb interaction can be promising therapeutic targets for leukemia with activated Evi1.
Blood 02/2011; 117(13):3617-28. · 9.90 Impact Factor
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Naoko Kato,
Jiro Kitaura,
Noriko Doki,
Yukiko Komeno, Naoko Watanabe-Okochi,
Katsuhiro Togami,
Fumio Nakahara,
Toshihiko Oki,
Yutaka Enomoto,
Yumi Fukuchi,
Hideaki Nakajima,
Yuka Harada,
Hironori Harada,
Toshio Kitamura
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ABSTRACT: Two types of mutations of a transcription factor CCAAT-enhancer binding protein α (C/EBPα) are found in leukemic cells of 5%-14% of acute myeloid leukemia (AML) patients: N-terminal mutations expressing dominant negative p30 and C-terminal mutations in the basic leucine zipper domain. Our results showed that a mutation of C/EBPα in one allele was observed in AML after myelodysplastic syndrome, while the 2 alleles are mutated in de novo AML. Unlike an N-terminal frame-shift mutant (C/EBPα-N(m))-transduced cells, a C-terminal mutant (C/EBPα-C(m))-transduced cells alone induced AML with leukopenia in mice 4-12 months after bone marrow transplantation. Coexpression of both mutants induced AML with marked leukocytosis with shorter latencies. Interestingly, C/EBPα-C(m) collaborated with an Flt3-activating mutant Flt3-ITD in inducing AML. Moreover, C/EBPα-C(m) strongly blocked myeloid differentiation of 32Dcl3 cells, suggesting its class II mutation-like role in leukemogenesis. Although C/EBPα-C(m) failed to inhibit transcriptional activity of wild-type C/EBPα, it suppressed the synergistic effect between C/EBPα and PU.1. On the other hand, C/EBPα-N(m) inhibited C/EBPα activation in the absence of PU.1, despite low expression levels of p30 protein generated by C/EBPα-N(m). Thus, 2 types of C/EBPα mutations are implicated in leukemo-genesis, involving different and cooperating molecular mechanisms.
Blood 09/2010; 117(1):221-33. · 9.90 Impact Factor
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Naoko Watanabe-Okochi,
Toshihiko Oki,
Yukiko Komeno,
Naoko Kato,
Koichiro Yuji,
Ryoichi Ono,
Yuka Harada,
Hironori Harada,
Yasuhide Hayashi,
Hideaki Nakajima,
Tetsuya Nosaka,
Jiro Kitaura,
Toshio Kitamura
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ABSTRACT: It is now conceivable that leukemogenesis requires two types of mutations, class I and class II mutations. We previously established a mouse bone marrow-derived HF6, an IL-3-dependent cell line, that was immortalized by a class II mutation MLL/SEPT6 and can be fully transformed by class I mutations such as FLT3 mutants. To understand the molecular mechanism of leukemogenesis, particularly progression of myelodysplastic syndrome (MDS) to acute leukemia, we made cDNA libraries from the samples of patients and screened them by expression-cloning to detect class I mutations that render HF6 cells factor-independent. We identified RasGRP4, an activator of Ras, as a candidate for class I mutation from three of six patients (MDS/MPD = 1, MDS-RA = 1, MDS/AML = 2, CMMoL/AML = 1 and AML-M2 = 1). To investigate the potential roles of RasGRP4 in leukemogenesis, we tested its in vivo effect in a mouse bone marrow transplantation (BMT) model. C57BL/6J mice transplanted with RasGRP4-transduced primary bone marrow cells died of T cell leukemia, myeloid leukemia, or myeloid leukemia with T cell leukemia. To further examine if the combination of class I and class II mutations accelerated leukemic transformation, we performed a mouse BMT model in which both AML1 mutant (S291fsX300) and RasGRP4 were transduced into bone marrow cells. The double transduction led to early onset of T cell leukemia but not of AML in the transplanted mice when compared to transduction of RasGRP4 alone. Thus, we have identified RasGRP4 as a gene potentially involved in leukemogenesis and suggest that RasGRP4 cooperates with AML1 mutations in T cell leukemogenesis as a class I mutation.
International journal of hematology 05/2009; 89(4):470-81. · 1.17 Impact Factor
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ABSTRACT: Myelodysplastic syndrome (MDS) is a hematopoietic stem-cell disorder characterized by trilineage dysplasia and susceptibility to acute myelogenous leukemia (AML). Analysis of molecular basis of MDS has been hampered by the heterogeneity of the disease. Recently, mutations of the transcription factor AML1/RUNX1 have been identified in 15% to 40% of MDS-refractory anemia with excess of blasts (RAEB) and MDS/AML. We performed mouse bone marrow transplantation (BMT) using bone marrow cells transduced with the AML1 mutants. Most mice developed MDS and MDS/AML-like symptoms within 4 to 13 months after BMT. Interestingly, among integration sites identified, Evi1 seemed to collaborate with an AML1 mutant harboring a point mutation in the Runt homology domain (D171N) to induce MDS/AML with an identical phenotype characterized by marked hepatosplenomegaly, myeloid dysplasia, leukocytosis, and biphenotypic surface markers. Collaboration between AML1-D171N and Evi1 was confirmed by a BMT model where coexpression of AML1-D171N and Evi1 induced acute leukemia of the same phenotype with much shorter latencies. On the other hand, a C-terminal truncated AML1 mutant (S291fsX300) induced pancytopenia with erythroid dysplasia in transplanted mice, followed by progression to MDS-RAEB or MDS/AML. Thus, we have developed a useful mouse model of MDS/AML that should help in the understanding of the molecular basis of MDS and the progression of MDS to overt leukemia.
Blood 05/2008; 111(8):4297-308. · 9.90 Impact Factor
