The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sukchul Bae - One of the best experts on this subject based on the ideXlab platform.
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the RUNX3 tumor suppressor upregulates bim in gastric epithelial cells undergoing transforming growth factor β induced apoptosis
Molecular and Cellular Biology, 2006Co-Authors: Takashi Yano, Kenichi Inoue, Kosei Ito, Hiroshi Fukamachi, Xinzi Chi, Heejun Wee, Hiroshi Ida, Philippe Bouillet, Andreas Strasser, Sukchul BaeAbstract:Genes involved in the transforming growth factor β (TGF-β) signaling pathway are frequently altered in several types of cancers, and a gastric tumor suppressor RUNX3 appears to be an integral component of this pathway. We reported previously that apoptosis is notably reduced in RUNX3−/− gastric epithelial cells. In the present study, we show that a proapoptotic gene Bim was transcriptionally activated by RUNX3 in the gastric cancer cell lines SNU16 and SNU719 treated with TGF-β. The human Bim promoter contains RUNX sites, which are required for its activation. Furthermore, a dominant negative form of RUNX3 comprised of amino acids 1 to 187 increased tumorigenicity of SNU16 by inhibiting Bim expression. In RUNX3−/− mouse gastric epithelium, Bim was down-regulated, and apoptosis was reduced to the same extent as that in Bim−/− gastric epithelium. We confirmed comparable expression of TGF-β1 and TGF-β receptors between wild-type and RUNX3−/− gastric epithelia and reduction of Bim in TGF-β1−/− stomach. These results demonstrate that RUNX3 is responsible for transcriptional up-regulation of Bim in TGF-β-induced apoptosis.
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the RUNX3 tumor suppressor upregulates bim in gastric epithelial cells undergoing transforming growth factor beta induced apoptosis
Molecular and Cellular Biology, 2006Co-Authors: Takashi Yano, Kenichi Inoue, Kosei Ito, Hiroshi Fukamachi, Xinzi Chi, Heejun Wee, Hiroshi Ida, Philippe Bouillet, Andreas Strasser, Sukchul BaeAbstract:Genes involved in the transforming growth factor beta (TGF-beta) signaling pathway are frequently altered in several types of cancers, and a gastric tumor suppressor RUNX3 appears to be an integral component of this pathway. We reported previously that apoptosis is notably reduced in RUNX3-/- gastric epithelial cells. In the present study, we show that a proapoptotic gene Bim was transcriptionally activated by RUNX3 in the gastric cancer cell lines SNU16 and SNU719 treated with TGF-beta. The human Bim promoter contains RUNX sites, which are required for its activation. Furthermore, a dominant negative form of RUNX3 comprised of amino acids 1 to 187 increased tumorigenicity of SNU16 by inhibiting Bim expression. In RUNX3-/- mouse gastric epithelium, Bim was down-regulated, and apoptosis was reduced to the same extent as that in Bim-/- gastric epithelium. We confirmed comparable expression of TGF-beta1 and TGF-beta receptors between wild-type and RUNX3-/- gastric epithelia and reduction of Bim in TGF-beta1-/- stomach. These results demonstrate that RUNX3 is responsible for transcriptional up-regulation of Bim in TGF-beta-induced apoptosis.
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transforming growth factor β stimulates p300 dependent RUNX3 acetylation which inhibits ubiquitination mediated degradation
Journal of Biological Chemistry, 2004Co-Authors: Yunhye Jin, Eunjoo Jeon, Yong Hee Lee, Joongkook Choi, Wunjae Kim, Kwang Youl Lee, Sukchul BaeAbstract:The Runt domain transcription factors (RUNXs) play essential roles in normal development and neoplasias. Genetic analyses of animals and humans have revealed the involvement of RUNX1 in hematopoiesis and leukemia, RUNX2 in osteogenesis and cleidocranial dysplasia, and RUNX3 in the development of T-cells and dorsal root ganglion neurons and in the genesis of gastric cancer. Here we report that RUNX3 is a target of the acetyltransferase activity of p300. The p300-dependent acetylation of three lysine residues protects RUNX3 from ubiquitin ligase Smurf-mediated degradation. The extent of the acetylation is up-regulated by the transforming growth factor-β signaling pathway and down-regulated by histone deacetylase activities. Our findings demonstrate that the level of RUNX3 protein is controlled by the competitive acetylation and deacetylation of the three lysine residues, revealing a new mechanism for the posttranslational regulation of RUNX3 expression.
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tumor suppressor activity of RUNX3
Oncogene, 2004Co-Authors: Sukchul Bae, Joongkook ChoiAbstract:Recent analyses have revealed that RUNX family members play important roles in both normal developmental processes and carcinogenesis. Of the three known RUNX family members, RUNX3 has been shown to be involved in neurogenesis of the dorsal root ganglia, T-cell differentiation and tumorigenesis of gastric epithelium. Deletion of the RUNX3 locus in mice resulted in hyperplasia of the gastric epithelium due to the stimulation of proliferation and suppression of apoptosis that was accompanied by a reduced sensitivity to TGF-β1. In primary human gastric cancer specimens, RUNX3 is frequently inactivated by allele loss or gene silencing due to promoter hypermethylation. The tumorigenicity of human gastric cancer cell lines in nude mice decreased as the level of RUNX3 expression increased, which indicates that RUNX3 is a bona fide tumor suppressor of gastric cancers.
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transcriptional silencing of the RUNX3 gene by cpg hypermethylation is associated with lung cancer
Biochemical and Biophysical Research Communications, 2004Co-Authors: Hye Ryeon Kim, Yoshiaki Ito, Yong Hee Lee, Joongkook Choi, Wunjae Kim, Kwang Youl Lee, Hwan Mook Kim, Hoguen Kim, Joon Chang, Sukchul BaeAbstract:RUNX family transcription factors are integral components of TGF-β signaling pathways and have been implicated in cell cycle regulation, differentiation, apoptosis, and malignant transformation. It was noted previously that allele loss and loss of expression of RUNX3 are causally involved in gastric carcinogenesis. Our results demonstrate that RUNX3 is inactivated by aberrant DNA methylation in approximately 19% of lung cancer cell lines and 24% of primary lung cancer specimens. RUNX3 methylation is tumor-specific, since it is not observed in surrounding normal lung tissues. Our results suggest that loss of RUNX3 expression by DNA hypermethylation is frequently associated with the evolution of lung cancer.
Nancy A Speck - One of the best experts on this subject based on the ideXlab platform.
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runx1 dose dependently regulates endochondral ossification during skeletal development and fracture healing
Journal of Bone and Mineral Research, 2012Co-Authors: Do Y Soung, Laleh Talebian, Christina J Matheny, Maren E Speck, Nancy A Speck, Rosa M Guzzo, Jay R Lieberman, Hicham DrissiAbstract:Runx1 is expressed in skeletal elements, but its role in fracture repair has not been analyzed. We created mice with a hypomorphic Runx1 allele (Runx1L148A) and generated Runx1L148A/− mice in which >50% of Runx1 activity was abrogated. Runx1L148A/− mice were viable but runted. Their growth plates had extended proliferating and hypertrophic zones, and the percentages of Sox9, Runx2 and RUNX3 positive cells were decreased. Femoral fracture experiments revealed delayed cartilaginous callus formation and the expression of chondrogenic markers was decreased. Conditional ablation of Runx1 in the mesenchymal progenitor cells of the limb with Prx1-Cre conferred no obvious limb phenotype; however cartilaginous callus formation was delayed following fracture. Embryonic limb bud-derived mesenchymal cells showed delayed chondrogenesis when the Runx1 allele was deleted ex vivo with adenoviral-expressed Cre. Collectively, our data suggest that Runx1 is required for commitment and differentiation of chondroprogenitor cells into the chondrogenic lineage.
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A Hypomorphic Cbfb Allele Reveals a Critical Dosage-Sensitive Function of Core Binding Factors at the Earliest Stages of T Cell Development.
Blood, 2005Co-Authors: Ivan Maillard, Laleh Talebian, Maren E Speck, Warren S Pear, Zhe Li, Daisuke Sugiyama, Nancy A SpeckAbstract:The family of core binding factors includes the DNA-binding subunits Runx1-3 and the common non-DNA binding partner CBFβ. Runx1 and CBFβ are essential for the emergence of hematopoietic stem cells during fetal development, but not for stem cell maintenance during later ontogeny. Runx1 is also required for megakaryocyte differentiation, B cell development, and for the DN2 to DN3 transition in thymocyte development. Runx2/CBFβ are critical for normal osteogenesis, and RUNX3 for CD4 silencing in CD8+ T cells, but their contribution to other steps of hematopoietic development is unknown. To examine the collective role of core binding factors in hematopoiesis, we generated a hypomorphic Cbfb allele ( Cbfb rss). CBFβ protein levels were reduced by approximately 2–3 fold in fetuses homozygous for the Cbfb rss allele ( Cbfb rss/rss), and 3–4 fold in fetuses carrying one hypomorphic and one knockout allele ( Cbfb rss/−). Cbfb rss/rss and Cbfb rss/− fetuses had normal erythroid and B cell development, and relatively mild abnormalities in megakaryocyte and granulocyte differentiation. In contrast, T cell development was very sensitive to an incremental reduction of CBFβ levels: mature thymocytes were decreased in Cbfb rss/rss fetuses, and virtually absent in Cbfb rss/−fetuses. We next assessed the development of Cbfb rss/rss and Cbfb rss/− fetal liver progenitors after transplantation to irradiated adult recipients, in competition with wild-type ( wt ) bone marrow cells. Wt , Cbfb rss/rss and Cbfb rss/− fetal progenitors replenished the erythroid, myeloid and B cell compartments equally well. The overall development of Cbfb rss/rss T cells was preserved, although CD4 expression was derepressed in double negative thymocytes. In Cbfb rss/− chimeras, mature thymocytes were entirely derived from competitor cells. Furthermore, the developmental block in Cbfb rss/− progenitors was present at the earliest stages of T cell development within the DN1 (ETP) and DN2 subsets. Our data define a critical CBFβ threshold for normal T cell development, and they situate an essential role of core binding factors during the earliest stages of T cell development. In addition, early thymopoiesis appeared more severely affected by reduced CBFβ dosage than by the lack of Runx1 (Ichikawa et al. , Nat Med 2004; Growney et al. , Blood 2005), suggesting that Runx2/3 may contribute to core binding factor activity in the T cell lineage.
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the cbfb smmhc oncoprotein inhibits binding of the runx1 runt domain to dna
Blood, 2005Co-Authors: John H Bushweller, Stephen M Lukasik, Nancy A SpeckAbstract:Core-binding factors (CBFs) are heterodimeric transcriptional factors consisting of a DNA-binding Runx1 (CBFα) subunit and a CBFβ subunit. Cbfβ allosterically increases the affinity of Runx1 for DNA ~2.5 fold. CBF subunits are encoded by four genes in mammals. RUNX1 (AML1), RUNX2, and RUNX3 encode for CBFα subunits, and CBFB encodes the CBFβ subunit. Homozygous disruption of either the Runx1 or the Cbfb genes in mice results in essentially identical phenotypes: midgestation embryonic lethality accompanied by extensive hemorrhaging and a profound block at the fetal liver stage of hematopoiesis. In humans, chromosomal rearrangements that disrupt the Runx1 and CBFB genes are associated with a significant percentage of leukemias. CBFβ is disrupted in acute myeloid leukemia by inv(16)(p13;q22), t(16;16), and del(16)(q22). These translocations result in the production of novel fusion proteins containing most of the CBFβ protein fused to the C-terminal coiled-coil domain from smooth muscle myosin heavy chain (SMMHC) encoded by the MYH11 gene. A knock-in of the CBFB-MYH11 allele in mice resulted in embryonic lethality with a profound block in hematopoietic development, the same phenotype observed for the Runx1 and Cbfb knockouts. We recently demonstrated that the CBFβ-SMMHC fusion protein binds to the DNA binding Runt domain from Runx1 with both higher affinity and altered stoichiometry relative to native CBFβ. We also provided NMR-based evidence for multiple sites of contact between Runx1 and CBFβ-SMMHC, proving the role of the SMMHC sequence in creating this altered affinity. Here we demonstrate that CBFβ-SMMHC inhibits DNA binding of the Runx1 Runt domain by ~6-fold for the CD4 dual-site silencer element. Cross-saturation NMR mapping on the Runt domain in complex with CBFβ-SMMHC reveals that the SMMHC portion of the oncoprotein makes contacts with β-strands 1 and 2 in the Runt domain. We propose that the inhibition of DNA-binding and increased affinity combine to mediate the dysregulation of Runx-regulated genes caused by CBFβ-SMMHC. These results also clearly suggest that targeting of the CBFβ-SMMHC protein for drug development may well be a viable approach for the treatment of the associated leukemia.
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biochemical and in vivo characterization of amino acid substitutions in the runx1 aml1 runt domain found in fpd aml aml m0 and cleidocranial dysplasia ccd patients
Blood, 2004Co-Authors: Christina J Matheny, Takeshi Corpora, Maren E Speck, Tinglei Gu, John H Bushweller, Nancy A SpeckAbstract:Runx1 and CBF β are the DNA-binding and non DNA-binding subunits of a core-binding factor that is required for hematopoiesis, and that is frequently mutated in leukemia. Runx2 is the DNA-binding subunit of a core-binding factor required for bone formation. Mono-allelic deletion, nonsense, frameshift, and missense mutations have been found in RUNX1 in familial platelet disorder with predisposition for acute myelogenous leukemia (FPD/AML) and in myelodysplastic syndrome (MDS), and biallelic mutations in RUNX1 are found in 20% of AML M0 patients. Similar types of mono-allelic mutations have been found in RUNX2 in patients with cleidocranial dysplasia (CCD), an inherited skeletal syndrome. FPD/AML and CCD pedigrees have revealed varying degrees of disease severity depending on the nature of the specific mutation. Additionally, it has been observed that mutations involving amino acids in the DNA binding Runt domain that directly contact DNA are associated primarily with Runx1 and hematopoietic disorders, while mutations predicted to disrupt CBF β binding or the Runt domain structure are found only in Runx2 in CCD patients. We introduced 21 amino acid substitutions into the Runt domain of Runx1 identified in FPD/AML, AML M0, and CCD patients, and quantified their effects on DNA binding, heterodimerization with CBFβ, and the Runt domain structure using yeast one- and two-hybrid, quantitative electrophoretic mobility shift, heteronuclear single quantum correlation spectroscopy, and urea denaturation experiments. To address the impact on in vivo function, several of these point mutations were engineered into the endogenous Runx1 allele in mice. These five mutations include: R177X, R174Q, T149A, T161A, and L148F. R177X is found in FPD/AML patients and truncates Runx1 two amino acids before the C-terminal boundary of the Runt domain. R174Q (found in FPD/AML and CCD) disrupts DNA binding 1000-fold, but does not disrupt CBFb binding or perturb the Runt domain fold. T149A (found only in CCD) disrupts CBFβ binding 13-fold while T161A (not found in patients) disrupts CBFβ binding 40-fold. Both T149A and T161A slightly perturb the Runt domain fold, but do not alter DNA binding affinity. L148F (found in CCD) also disrupts the Runt domain fold, and decreases DNA binding. All animals heterozygous for these alleles are viable. Mice homozygous for R177X and R174Q die during gestation. Mice homozygous for the T149A and T161A mutations, on the other hand, are born at normal Mendelian frequencies, but 62% and 100%, respectively, die by or at three weeks of age from an undetermined cause. The effects of these mutations on hematopoietic progenitor and platelet numbers, both of which are affected in FPD/AML patients, will be presented. We conclude that mutations that affect CBFβ binding result in hypomorphic Runx1 alleles, while mutations involving DNA contacts result in more severe inactivation of Runx1 function. Thus FPD/AML, AML M0, and MDS require mutations that severely inactivate Runx1 function, while CCD can result from more subtle alterations in Runx2.
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mutagenesis of the runt domain defines two energetic hot spots for heterodimerization with the core binding factor β subunit
Journal of Biological Chemistry, 2003Co-Authors: Lina Zhang, Takeshi Corpora, Matthew D Cheney, Alan J Warren, Jerónimo Bravo, John H Bushweller, Zhe Li, Padmanava Pradhan, Nancy A SpeckAbstract:Abstract Core-binding factors (CBFs) are a small family of heterodimeric transcription factors that play critical roles in several developmental pathways and in human disease. Mutations in CBF genes are found in leukemias, bone disorders, and gastric cancers. CBFs consist of a DNA-binding CBFα subunit (Runx1, Runx2, or RUNX3) and a non-DNA-binding CBFβ subunit. CBFα binds DNA in a sequence-specific manner, whereas CBFβ enhances DNA binding by CBFα. Both DNA binding and heterodimerization with CBFβ are mediated by a single domain in the CBFα subunits known as the “Runt domain.” We analyzed the energetic contribution of amino acids in the Runx1 Runt domain to heterodimerization with CBFβ. We identified two energetic “hot spots” that were also found in a similar analysis of CBFβ (Tang, Y.-Y., Shi, J., Zhang, L., Davis, A., Bravo, J., Warren, A. J., Speck, N. A., and Bushweller, J. H. (2000) J. Biol. Chem. 275, 39579–39588). The importance of the hot spot residues for Runx1 function was demonstrated in in vivo transient transfection assays. These data refine the structural analyses and further our understanding of the Runx1-CBFβ interface.
Shari Meyers - One of the best experts on this subject based on the ideXlab platform.
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runx1 aml 1 and runx2 aml 3 cooperate with prostate derived ets factor to activate transcription from the psa upstream regulatory region
Journal of Cellular Biochemistry, 2006Co-Authors: Marcie Fowler, Erkut Borazanci, Laura L Mcghee, Shannon Walls Pylant, Jill B Williams, Jonathan D Glass, Nathan J Davis, Shari MeyersAbstract:The RUNX transcription factors (RUNX1, RUNX2, and RUNX3) play essential roles in hematopoiesis and skeletal development. Consistent with these roles in differentiation and cell cycle, the activity of both RUNX1 and RUNX3 is perturbed in cancer. To determine a role for the RUNX factors in prostate biology, we investigated the expression of RUNX factors in prostate epithelial cell lines and normal prostate tissue. RUNX1, RUNX2, and RUNX3 were expressed in both normal prostate tissue and an immortalized, non-transformed cell line. We found that prostate cancer-derived cell lines expressed RUNX1 and RUNX2, but not RUNX3. Next, we sought to identify prostate-specific genes whose expression could be regulated by RUNX proteins. Four consensus RUNX sites are located within the prostate-specific antigen (PSA) regulatory region. Chromatin immunoprecipitation (ChIP) analysis showed that RUNX1 is specifically bound to the PSA regulatory region in LNCaP cells. RUNX1 and RUNX2 activated the PSA regulatory region alone or cooperatively with prostate-derived ETS factor (PDEF) and RUNX1 physically associated with PDEF. Taken together, our results suggest that RUNX factors participate in prostate epithelial cell function and cooperate with an Ets transcription factor to regulate PSA gene expression.
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runx1 aml 1 and runx2 aml 3 cooperate with prostate derived ets factor to activate transcription from the psa upstream regulatory region
Journal of Cellular Biochemistry, 2006Co-Authors: Marcie Fowler, Erkut Borazanci, Laura L Mcghee, Shannon Walls Pylant, Jill B Williams, Nathan J Davis, Shari Meyers, Jonathan GlassAbstract:The RUNX transcription factors (RUNX1, RUNX2, and RUNX3) play essential roles in hematopoiesis and skeletal development. Consistent with these roles in differentiation and cell cycle, the activity of both RUNX1 and RUNX3 is perturbed in cancer. To determine a role for the RUNX factors in prostate biology, we investigated the expression of RUNX factors in prostate epithelial cell lines and normal prostate tissue. RUNX1, RUNX2, and RUNX3 were expressed in both normal prostate tissue and an immortalized, non-transformed cell line. We found that prostate cancer-derived cell lines expressed RUNX1 and RUNX2, but not RUNX3. Next, we sought to identify prostate-specific genes whose expression could be regulated by RUNX proteins. Four consensus RUNX sites are located within the prostate-specific antigen (PSA) regulatory region. Chromatin immunoprecipitation (ChIP) analysis showed that RUNX1 is specifically bound to the PSA regulatory region in LNCaP cells. RUNX1 and RUNX2 activated the PSA regulatory region alone or cooperatively with prostate-derived ETS factor (PDEF) and RUNX1 physically associated with PDEF. Taken together, our results suggest that RUNX factors participate in prostate epithelial cell function and cooperate with an Ets transcription factor to regulate PSA gene expression. J. Cell. Biochem. © 2005 Wiley-Liss, Inc.
Toshihisa Komori - One of the best experts on this subject based on the ideXlab platform.
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contribution of runt related transcription factor 2 to the pathogenesis of osteoarthritis in mice after induction of knee joint instability
Arthritis & Rheumatism, 2006Co-Authors: Satoru Kamekura, Takashi Shimoaka, Zenjiro Maruyama, Shu Takeda, Toshihisa Komori, Yosuke Kawasaki, Kazuto Hoshi, Hirotaka Chikuda, Shingo Sato, Gerard KarsentyAbstract:Objective By producing instability in mouse knee joints, we attempted to determine the involvement of runt-related transcription factor 2 (RUNX-2), which is required for chondrocyte hypertrophy, in the development of osteoarthritis (OA). Methods An experimental mouse OA model was created by surgical transection of the medial collateral ligament and resection of the medial meniscus of the knee joints of heterozygous RUNX-2–deficient (Runx2+/−) mice and wild-type littermates. Cartilage destruction and osteophyte formation in the medial tibial cartilage were compared by histologic and radiographic analyses. Localization of type X collagen and matrix metalloproteinase 13 (MMP-13) was examined by immunohistochemistry. Localization of RUNX-2 was determined by X-Gal staining in heterozygous RUNX-2–deficient mice with the lacZ gene insertion at the Runx2-deletion site (Runx2+/lacZ). Messenger RNA levels of type X collagen, MMP-13, and RUNX-2 were examined by real-time reverse transcriptase–polymerase chain reaction analysis. Results RUNX-2 was induced in the articular cartilage of wild-type mice at the early stage of OA, almost simultaneously with type X collagen but earlier than MMP-13. Runx2+/− and Runx2+/lacZ mice showed normal skeletal development and articular cartilage; however, after induction of knee joint instability, they exhibited decreased cartilage destruction and osteophyte formation, along with reduced type X collagen and MMP-13 expression, as compared with wild-type mice. Conclusion RUNX-2 contributes to the pathogenesis of OA through chondrocyte hypertrophy and matrix breakdown after the induction of joint instability.
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regulation of skeletal development by the runx family of transcription factors
Journal of Cellular Biochemistry, 2005Co-Authors: Toshihisa KomoriAbstract:The Runx (runt-related protein) family of transcription factors plays important roles in different tissues and cell lineages. Runx1 determines commitment to the hematopoietic cell lineage and Runx2 determines commitment to the osteoblastic lineage. Cbfβ is required for Runx1- and Runx2-dependent transcriptional regulation. Runx2 interacts with many other transcription factors and co-regulators in the transcriptional regulation of its target genes. Runx2 is essential for the commitment of multipotent mesenchymal cells into the osteoblastic lineage and inhibits adipocyte differentiation. Runx2 induces the gene expression of bone matrix proteins, while keeping the osteoblastic cells in an immature stage. Runx2 and RUNX3 have redundant functions in chondrocytes, and they are essential for chondrocyte maturation. Runx2 directly induces Indian hedgehog (Ihh) expression and co-ordinates the proliferation and differentiation of chondrocytes. Therefore, elucidation of the signaling pathways through Runx2 and RUNX3 will unravel the complex mechanism of skeletal development. © 2005 Wiley-Liss, Inc.
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runx2 and RUNX3 are essential for chondrocyte maturation and runx2 regulates limb growth through induction of indian hedgehog
Genes & Development, 2004Co-Authors: Carolina A Yoshida, Kei Yamana, Tatsuya Furuichi, Akira Zanma, Kenichi Inoue, Kenji Takada, Hiromitsu Yamamoto, Toshihisa KomoriAbstract:The differentiation of mesenchymal cells into chondrocytes and chondrocyte proliferation and maturation are fundamental steps in skeletal development. Runx2 is essential for osteoblast differentiation and is involved in chondrocyte maturation. Although chondrocyte maturation is delayed in Runx2-deficient (Runx2(-/-)) mice, terminal differentiation of chondrocytes does occur, indicating that additional factors are involved in chondrocyte maturation. We investigated the involvement of RUNX3 in chondrocyte differentiation by generating Runx2-and-RUNX3-deficient (Runx2(-/-)3(-/-)) mice. We found that chondrocyte differentiation was inhibited depending on the dosages of Runx2 and RUNX3, and Runx2(-/-)3(-/-) mice showed a complete absence of chondrocyte maturation. Further, the length of the limbs was reduced depending on the dosages of Runx2 and RUNX3, due to reduced and disorganized chondrocyte proliferation and reduced cell size in the diaphyses. Runx2(-/-)3(-/-) mice did not express Ihh, which regulates chondrocyte proliferation and maturation. Adenoviral introduction of Runx2 in Runx2(-/-) chondrocyte cultures strongly induced Ihh expression. Moreover, Runx2 directly bound to the promoter region of the Ihh gene and strongly induced expression of the reporter gene driven by the Ihh promoter. These findings demonstrate that Runx2 and RUNX3 are essential for chondrocyte maturation and that Runx2 regulates limb growth by organizing chondrocyte maturation and proliferation through the induction of Ihh expression.
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Requisite roles of Runx2 and Cbfb in skeletal development.
Journal of bone and mineral metabolism, 2003Co-Authors: Toshihisa KomoriAbstract:Each Runx (runt-related gene) protein exerts a fundamental role in different cell lineages. Runx2 is essential for osteoblast differentiation and plays an important role in chondrocyte maturation. Runx2 determines the lineage of osteoblastic cells from multipotent mesenchymal cells, enhances osteoblast differentiation at an early stage, and inhibits osteoblast differentiation at a late stage. In addition, Runx2 is involved in the production of bone matrix proteins. Further, Runx2 is a positive regulator of chondrocyte maturation and is involved in vascular invasion into the cartilage. Core binding factor β (Cbfb) is a cotranscription factor which forms a heterodimer with Runx proteins. Cbfb is required for the functions of Runx1 and Runx2. Thus, Runx2/Cbfb heterodimers play essential roles in skeletal development.
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differential requirements for runx proteins in cd4 repression and epigenetic silencing during t lymphocyte development
Cell, 2002Co-Authors: Ichiro Taniuchi, Takeshi Egawa, Motomi Osato, Toshihisa Komori, Yoshiaki Ito, Sukchul Bae, Mary Jean Sunshine, Dan R LittmanAbstract:T lymphocytes differentiate in discrete stages within the thymus. Immature thymocytes lacking CD4 and CD8 coreceptors differentiate into double-positive cells (CD4(+)CD8(+)), which are selected to become either CD4(+)CD8(-)helper cells or CD4(-)CD8(+) cytotoxic cells. A stage-specific transcriptional silencer regulates expression of CD4 in both immature and CD4(-)CD8(+) thymocytes. We show here that binding sites for Runt domain transcription factors are essential for CD4 silencer function at both stages, and that different Runx family members are required to fulfill unique functions at each stage. Runx1 is required for active repression in CD4(-)CD8(-) thymocytes whereas RUNX3 is required for establishing epigenetic silencing in cytotoxic lineage thymocytes. RUNX3-deficient cytotoxic T cells, but not helper cells, have defective responses to antigen, suggesting that Runx proteins have critical functions in lineage specification and homeostasis of CD8-lineage T lymphocytes.
Kosei Ito - One of the best experts on this subject based on the ideXlab platform.
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central role of core binding factor β2 in mucosa associated lymphoid tissue organogenesis in mouse
PLOS ONE, 2015Co-Authors: Takahiro Nagatake, Ichiro Taniuchi, Satoshi Fukuyama, Shintaro Sato, Hideaki Okura, Masashi Tachibana, Kosei Ito, Michiko Shimojou, Naomi Matsumoto, Hidehiko SuzukiAbstract:Mucosa-associated lymphoid tissue (MALT) is a group of secondary and organized lymphoid tissue that develops at different mucosal surfaces. Peyer’s patches (PPs), nasopharynx-associated lymphoid tissue (NALT), and tear duct-associated lymphoid tissue (TALT) are representative MALT in the small intestine, nasal cavity, and lacrimal sac, respectively. A recent study has shown that transcriptional regulators of core binding factor (Cbf) β2 and promotor-1-transcribed Runt-related transcription factor 1 (P1-Runx1) are required for the differentiation of CD3−CD4+CD45+ lymphoid tissue inducer (LTi) cells, which initiate and trigger the developmental program of PPs, but the involvement of this pathway in NALT and TALT development remains to be elucidated. Here we report that Cbfβ2 plays an essential role in NALT and TALT development by regulating LTi cell trafficking to the NALT and TALT anlagens. Cbfβ2 was expressed in LTi cells in all three types of MALT examined. Indeed, similar to the previous finding for PPs, we found that Cbfβ2−/− mice lacked NALT and TALT lymphoid structures. However, in contrast to PPs, NALT and TALT developed normally in the absence of P1-Runx1 or other Runx family members such as Runx2 and RUNX3. LTi cells for NALT and TALT differentiated normally but did not accumulate in the respective lymphoid tissue anlagens in Cbfβ2−/− mice. These findings demonstrate that Cbfβ2 is a central regulator of the MALT developmental program, but the dependency of Runx proteins on the lymphoid tissue development would differ among PPs, NALT, and TALT.
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cbfb regulates bone development by stabilizing runx family proteins
Journal of Bone and Mineral Research, 2015Co-Authors: Xin Qin, Ichiro Taniuchi, Kosei Ito, Qing Jiang, Yuki Matsuo, Tetsuya Kawane, Hisato Komori, Takeshi Moriishi, Yosuke Kawai, Satoshi RokutandaAbstract:Runx family proteins, Runx1, Runx2, and RUNX3, play important roles in skeletal development. Runx2 is required for osteoblast differentiation and chondrocyte maturation, and haplodeficiency of RUNX2 causes cleidocranial dysplasia, which is characterized by open fontanelles and sutures and hypoplastic clavicles. Cbfb forms a heterodimer with Runx family proteins and enhances their DNA-binding capacity. Cbfb-deficient (Cbfb(-/-) ) mice die at midgestation because of the lack of fetal liver hematopoiesis. We previously reported that the partial rescue of hematopoiesis in Cbfb(-/-) mice revealed the requirement of Cbfb in skeletal development. However, the precise functions of Cbfb in skeletal development still remain to be clarified. We deleted Cbfb in mesenchymal cells giving rise to both chondrocyte and osteoblast lineages by mating Cbfb(fl/fl) mice with Dermo1 Cre knock-in mice. Cbfb(fl/fl/Cre) mice showed dwarfism, both intramembranous and endochondral ossifications were retarded, and chondrocyte maturation and proliferation and osteoblast differentiation were inhibited. The differentiation of chondrocytes and osteoblasts were severely inhibited in vitro, and the reporter activities of Ihh, Col10a1, and Bglap2 promoter constructs were reduced in Cbfb(fl/fl/Cre) chondrocytes or osteoblasts. The proteins of Runx1, Runx2, and RUNX3 were reduced in the cartilaginous limb skeletons and calvariae of Cbfb(fl/fl/Cre) embryos compared with the respective protein in the respective tissue of Cbfb(fl/fl) embryos at E15.5, although the reduction of Runx2 protein in calvariae was much milder than that in cartilaginous limb skeletons. All of the Runx family proteins were severely reduced in Cbfb(fl/fl/Cre) primary osteoblasts, and Runx2 protein was less stable in Cbfb(fl/fl/Cre) osteoblasts than Cbfb(fl/fl) osteoblasts. These findings indicate that Cbfb is required for skeletal development by regulating chondrocyte differentiation and proliferation and osteoblast differentiation; that Cbfb plays an important role in the stabilization of Runx family proteins; and that Runx2 protein stability is less dependent on Cbfb in calvariae than in cartilaginous limb skeletons.
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claudin 1 has tumor suppressive activity and is a direct target of RUNX3 in gastric epithelial cells
Gastroenterology, 2010Co-Authors: Ti Ling Chang, Kosei Ito, Manuel Saltotellez, Qiang Liu, Hiroshi Fukamachi, Khay Guan Yeoh, Yoshiaki ItoAbstract:Background & Aims The transcription factor RUNX3 is a gastric tumor suppressor. Tumorigenic RUNX3 −/− gastric epithelial cells attach weakly to each other, compared with nontumorigenic RUNX3 +/+ cells. We aimed to identify RUNX3 target genes that promote cell-cell contact to improve our understanding of RUNX3's role in suppressing gastric carcinogenesis. Methods We compared gene expression profiles of RUNX3 +/+ and RUNX3 −/− cells and observed down-regulation of genes associated with cell-cell adhesion in RUNX3 −/− cells. Reporter, mobility shift, and chromatin immunoprecipitation assays were used to examine the regulation of these genes by RUNX3. Tumorigenesis assays and immunohistological analyses of human gastric tumors were performed to confirm the role of the candidate genes in gastric tumor development. Results Mobility shift and chromatin immunoprecipitation assays revealed that the promoter activity of the gene that encodes the tight junction protein claudin-1 was up-regulated via the binding of RUNX3 to the RUNX consensus sites. The tumorigenicity of gastric epithelial cells from RUNX3 −/− mice was significantly reduced by restoration of claudin-1 expression, whereas knockdown of claudin-1 increased the tumorigenicity of human gastric cancer cells. Concomitant expression of RUNX3 and claudin-1 was observed in human normal gastric epithelium and cancers. Conclusions The tight junction protein claudin-1 has gastric tumor suppressive activity and is a direct transcriptional target of RUNX3. Claudin-1 is down-regulated during the epithelial-mesenchymal transition; RUNX3 might therefore act as a tumor suppressor to antagonize the epithelial-mesenchymal transition.
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RUNX3 is frequently inactivated by dual mechanisms of protein mislocalization and promoter hypermethylation in breast cancer
Cancer Research, 2006Co-Authors: Quek Choon Lau, Kosei Ito, Erna Raja, Manuel Saltotellez, Qiang Liu, Masafumi Inoue, Thomas C Putti, Marie LohAbstract:A tumor suppressor function has been attributed to RUNX3, a member of the RUNX family of transcription factors. Here, we examined alterations in the expression of three members, RUNX1, RUNX2, and RUNX3, and their interacting partner, CBF-beta, in breast cancer. Among them, RUNX3 was consistently underexpressed in breast cancer cell lines and primary tumors. Fifty percent of the breast cancer cell lines (n = 19) showed hypermethylation at the promoter region and displayed significantly lower levels of RUNX3 mRNA expression (P < 0.0001) and protein (P < 0.001). In primary Singaporean breast cancers, 9 of 44 specimens showed undetectable levels of RUNX3 by immunohistochemistry. In 35 of 44 tumors, however, low levels of RUNX3 protein were present. Remarkably, in each case, protein was mislocalized to the cytoplasm. In primary tumors, hypermethylation of RUNX3 was observed in 23 of 44 cases (52%) and was undetectable in matched adjacent normal breast epithelium. Mislocalization of the protein, with or without methylation, seems to account for RUNX3 inactivation in the vast majority of the tumors. In in vitro and in vivo assays, RUNX3 behaved as a growth suppressor in breast cancer cells. Stable expression of RUNX3 in MDA-MB-231 breast cancer cells led to a more cuboidal phenotype, significantly reduced invasiveness in Matrigel invasion assays, and suppressed tumor formation in immunodeficient mice. This study provides biological and mechanistic insights into RUNX3 as the key member of the family that plays a role in breast cancer. Frequent protein mislocalization and methylation could render RUNX3 a valuable marker for early detection and risk assessment.
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the RUNX3 tumor suppressor upregulates bim in gastric epithelial cells undergoing transforming growth factor β induced apoptosis
Molecular and Cellular Biology, 2006Co-Authors: Takashi Yano, Kenichi Inoue, Kosei Ito, Hiroshi Fukamachi, Xinzi Chi, Heejun Wee, Hiroshi Ida, Philippe Bouillet, Andreas Strasser, Sukchul BaeAbstract:Genes involved in the transforming growth factor β (TGF-β) signaling pathway are frequently altered in several types of cancers, and a gastric tumor suppressor RUNX3 appears to be an integral component of this pathway. We reported previously that apoptosis is notably reduced in RUNX3−/− gastric epithelial cells. In the present study, we show that a proapoptotic gene Bim was transcriptionally activated by RUNX3 in the gastric cancer cell lines SNU16 and SNU719 treated with TGF-β. The human Bim promoter contains RUNX sites, which are required for its activation. Furthermore, a dominant negative form of RUNX3 comprised of amino acids 1 to 187 increased tumorigenicity of SNU16 by inhibiting Bim expression. In RUNX3−/− mouse gastric epithelium, Bim was down-regulated, and apoptosis was reduced to the same extent as that in Bim−/− gastric epithelium. We confirmed comparable expression of TGF-β1 and TGF-β receptors between wild-type and RUNX3−/− gastric epithelia and reduction of Bim in TGF-β1−/− stomach. These results demonstrate that RUNX3 is responsible for transcriptional up-regulation of Bim in TGF-β-induced apoptosis.
