110 research outputs found

    Analysis of an alternative human CD133 promoter reveals the implication of Ras/ERK pathway in tumor stem-like hallmarks

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    <p>Abstract</p> <p>Background</p> <p>An increasing number of studies support the presence of stem-like cells in human malignancies. These cells are primarily responsible for tumor initiation and thus considered as a potential target to eradicate tumors. CD133 has been identified as an important cell surface marker to enrich the stem-like population in various human tumors. To reveal the molecular machinery underlying the stem-like features in tumor cells, we analyzed a promoter of <it>CD133 </it>gene using human colon carcinoma Caco-2 and synovial sarcoma Fuji cells, which endogenously express <it>CD133 </it>gene.</p> <p>Results</p> <p>A reporter analysis revealed that P5 promoter, located far upstream in a human <it>CD133 </it>gene locus, exhibits the highest activity among the five putative promoters (P1 to P5). Deletion and mutation analysis identified two ETS binding sites in the P5 region as being essential for its promoter activity. Electrophoretic mobility shift assays demonstrated the specific binding between nuclear factors and the ETS binding sequence. Overexpression of dominant-negative forms of Ets2 and Elk1 resulted in the significant decrease of P5 activity. Furthermore, treatment of Fuji cells with a specific MEK/ERK inhibitor, U0126, also markedly decreased CD133 expression, but there was no significant effect in Caco-2 cells, suggesting cell type-specific regulation of CD133 expression. Instead, the side population, another hallmark of TSLCs, was dramatically diminished in Caco-2 cells by U0126. Finally, Ras-mediated oncogenic transformation in normal human astrocytes conferred the stem-like capability to form neurosphere-like colonies with the increase of <it>CD133 </it>mRNA expression.</p> <p>Conclusions</p> <p>In conclusion, the Ras/ERK pathway at least in part contributes to the maintenance and the acquisition of stem-like hallmarks, although the extent of its contribution is varied in a cell type-specific manner. These findings could help our comprehensive understanding of tumor stemness, and also improve the development of eradicative therapies against human malignancies.</p

    Human NINEIN polymorphism at codon 1111 is associated with the risk of colorectal cancer

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    NINEIN serves an essential role in centrosome function as a microtubule organizing center, and in the reformation of the interphase centrosome architecture following mitosis. In the present study, the association between NINEIN Pro1111Ala (rs2236316), a missense single nucleotide polymorphism, and the risk of colorectal cancer (CRC), related to smoking and alcohol consumption habits in 200 patients with CRC and 1,141 cancer‑free control participants were assessed in a case‑control study performed in Japan. The results showed that the NINEIN Ala/Ala genotype compared with the Pro/Pro genotype was significantly more associated with an increased risk of CRC, and the males with the Ala/Ala genotype exhibited a significantly increased risk of CRC compared with those with Pro/Pro and Pro/Ala genotypes. Stratified analyses of the Ala/Ala genotype with CRC risk further showed an increased association in never/light drinkers (<23 g of ethanol/day), in male never/light drinkers and in male patients with rectal cancer. These findings suggest that the genetic variant of the NINEIN Pro1111Ala polymorphism has a significant effect on CRC susceptibility in the Japanese population

    Cationized gelatin-HVJ envelope with sodium borocaptate improved the BNCT efficacy for liver tumors in vivo

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    <p>Abstract</p> <p>Background</p> <p>Boron neutron capture therapy (BNCT) is a cell-selective radiation therapy that uses the alpha particles and lithium nuclei produced by the boron neutron capture reaction. BNCT is a relatively safe tool for treating multiple or diffuse malignant tumors with little injury to normal tissue. The success or failure of BNCT depends upon the <sup>10</sup>B compound accumulation within tumor cells and the proximity of the tumor cells to the body surface. To extend the therapeutic use of BNCT from surface tumors to visceral tumors will require <sup>10</sup>B compounds that accumulate strongly in tumor cells without significant accumulation in normal cells, and an appropriate delivery method for deeper tissues.</p> <p>Hemagglutinating Virus of Japan Envelope (HVJ-E) is used as a vehicle for gene delivery because of its high ability to fuse with cells. However, its strong hemagglutination activity makes HVJ-E unsuitable for systemic administration.</p> <p>In this study, we developed a novel vector for <sup>10</sup>B (sodium borocaptate: BSH) delivery using HVJ-E and cationized gelatin for treating multiple liver tumors with BNCT without severe adverse events.</p> <p>Methods</p> <p>We developed cationized gelatin conjugate HVJ-E combined with BSH (CG-HVJ-E-BSH), and evaluated its characteristics (toxicity, affinity for tumor cells, accumulation and retention in tumor cells, boron-carrying capacity to multiple liver tumors <it>in vivo</it>, and bio-distribution) and effectiveness in BNCT therapy in a murine model of multiple liver tumors.</p> <p>Results</p> <p>CG-HVJ-E reduced hemagglutination activity by half and was significantly less toxic in mice than HVJ-E. Higher <sup>10</sup>B concentrations in murine osteosarcoma cells (LM8G5) were achieved with CG-HVJ-E-BSH than with BSH. When administered into mice bearing multiple LM8G5 liver tumors, the tumor/normal liver ratios of CG-HVJ-E-BSH were significantly higher than those of BSH for the first 48 hours (<it>p < 0.05</it>). In suppressing the spread of tumor cells in mice, BNCT treatment was as effective with CG-HVJ-E-BSH as with BSH containing a 35-fold higher <sup>10</sup>B dose. Furthermore, CG-HVJ-E-BSH significantly increased the survival time of tumor-bearing mice compared to BSH at a comparable dosage of <sup>10</sup>B.</p> <p>Conclusion</p> <p>CG-HVJ-E-BSH is a promising strategy for the BNCT treatment of visceral tumors without severe adverse events to surrounding normal tissues.</p

    Single nucleosome imaging reveals loose genome chromatin networks via active RNA polymerase II.

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nagashima, R., Hibino, K., Ashwin, S. S., Babokhov, M., Fujishiro, S., Imai, R., Nozaki, T., Tamura, S., Tani, T., Kimura, H., Shribak, M., Kanemaki, M. T., Sasai, M., & Maeshima, K. Single nucleosome imaging reveals loose genome chromatin networks via active RNA polymerase II. Journal of Cell Biology, 218(5), (2019):1511-1530, doi:10.1083/jcb.201811090.Although chromatin organization and dynamics play a critical role in gene transcription, how they interplay remains unclear. To approach this issue, we investigated genome-wide chromatin behavior under various transcriptional conditions in living human cells using single-nucleosome imaging. While transcription by RNA polymerase II (RNAPII) is generally thought to need more open and dynamic chromatin, surprisingly, we found that active RNAPII globally constrains chromatin movements. RNAPII inhibition or its rapid depletion released the chromatin constraints and increased chromatin dynamics. Perturbation experiments of P-TEFb clusters, which are associated with active RNAPII, had similar results. Furthermore, chromatin mobility also increased in resting G0 cells and UV-irradiated cells, which are transcriptionally less active. Our results demonstrated that chromatin is globally stabilized by loose connections through active RNAPII, which is compatible with models of classical transcription factories or liquid droplet formation of transcription-related factors. Together with our computational modeling, we propose the existence of loose chromatin domain networks for various intra-/interchromosomal contacts via active RNAPII clusters/droplets.We thank Dr. Y. Hiromi, Dr. S. Hirose, Dr. H. Seino, and Dr. S. Ide for critical reading of this manuscript. We thank Dr. S. Ide, Dr. D. Kaida, Dr. T. Nagai, Dr. V. Doye, Dr. G. Felsenfeld, and Dr. K. Horie for valuable help and materials. We also thank the Maeshima laboratory members for helpful discussions and support. R. Imai and T. Nozaki are Japan Society for the Promotion of Science Fellows. R. Nagashima was supported by 2017 SOKENDAI Short-Stay Study Abroad Program. This work was supported by a Japan Society for the Promotion of Science grant (16H04746), Takeda Science Foundation, RIKEN Pioneering Project, a Japan Science and Technology Agency Core Research for Evolutional Science and Technology grant (JPMJCR15G2), a National Institute of General Medical Sciences grant (R01-GM101701), and National Institute of Genetics JOINT (2016-A2 (6))

    Human RAD 17 Polymorphism at Codon 546 Is Associated with the Risk of Colorectal Cancer

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    Human RAD17 acts as an activator of checkpoint signals in response to DNA damage. Here we evaluated the association of hRAD17 Leu546Arg (rs1045051), a missense single nucleotide polymorphism, with the risk of colorectal cancer (CRC) in relation to smoking and alcohol consumption habits in 212 CRC patients and 1,142 cancer-free controls in a case-control study conducted in Japan. The results showed that the hRAD17 Leu/Arg genotype compared to the Leu/Leu genotypes was significantly associated with the protective effect on CRC risk with the adjusted odds ratio (OR) of 0.68 [95% confidence interval (CI): 0.49−0.95, p=0.024], and the males with the Arg/Arg genotype had a greater risk of CRC compared to those with the Leu/Leu and Leu/Arg genotypes (OR=1.87, 95%CI 1.03−3.40, p=0.04). In stratified studies, the protective effect of the Leu/Arg genotype on CRC risk was markedly higher in the light smokers (< 20 pack years) (OR=0.61, 95%CI 0.40−0.94, p=0.024) and the rectal cancer patients (OR=0.49, 95%CI 0.31−0.78, p=0.003). The risk of the Arg/Arg genotype was associated with heavy smoking (≥ 20 pack-years) (OR=2.24, 95%CI 1.09−4.61, p=0.03). These findings suggest that the genetic variant of hRAD17 Leu546Arg polymorphism has a significant effect on CRC susceptibility in Japanese

    Mesenchymal Stem Cells from Bone Marrow Enhance Neovascularization and Stromal Cell Proliferation in Rat Ischemic Limb in the Early Phase after plantation

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    Accumulating evidence from animal studies shows that the administration of mesenchymal stem cells (MSCs) from adult bone marrow ameliorates tissue damage after ischemic injury. In the present study we investigated the efficacy of MSC implantation into a hindlimb ischemia model over a short-term period to elucidate the effects conferred within the early phase after treatment. MSCs from rats expressing green fluorescence protein (GFP) were injected into rat ischemic limbs. Laser Doppler perfusion imaging revealed significantly higher blood perfusion recovery in the MSC group than in the control group on days 3 and 7 after the treatment. The capillary / muscle fiber ratio in ischemic muscle was also significantly higher in the MSC group than in the controls in a histological study. In spite of these benefits, we found no evident engraftment of the GFP-positive cells, and instead, the MSC treatment induced a proliferation of resident stromal cells in the perivascular area of the ischemic muscle, some of which produced vascular endothelial growth factor. The present study suggested that MSC therapy promotes neovascularization even in the early phase, both directly through endothelial proliferation and indirectly through activation of the resident stromal cells
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