Breast cancer is the most common malignancy and a major cause of cancer-related death among Canadian women. Although treatment of primary breast tumours is highly successful through surgery, metastatic breast cancer is difficult to treat. Cancer progression and metastasis require the accumulation of numerous genetic and epigenetic alterations. Normal cells that acquire such alterations can transform into cancer cells, resulting in primary tumour formation. Primary tumours are a heterogeneous population, containing cells of various metastatic potentials. Cells that acquire a high potential for metastasis can spread to secondary locations. Our model system consists of two subpopulations, with different metastatic potential, derived from the same rat mammary adenocarcinoma. Using this model, a differentially expressed novel gene, termed MS-1, was discovered. Due to significant expression of this gene in the poorly metastatic subpopulation and lack of expression in the highly metastatic subpopulation, MS-1 may have involvement in metastasis suppression. Several breast cancer metastasis suppressor genes have been identified on the basis that they are down-regulated during the progression of metastasis. Epigenetic mechanisms, such as DNA methylation, account for loss of expression in several of these genes. Hypermethylation of CpG islands within gene promoters results in deacetylation of histone proteins and produces a compact chromatin structure that is unfavourable for transcription. A CpG island spans the 5 untranslated region, exon 1 and part of intron 1 of the MS-1 gene. Our data reveals aberrant methylation patterns of this CpG island in our model. Also, MS-1 expression appears to be partially induced by both DNA methylation and histone deacetylation inhibitors. Following a screen of several cancer cell lines of various metastatic potential, it appears that the presence of DNA methylation in the CpG island of MS-1 correlates with the lack of MS-1 expression. Therefore, these results suggest that MS-1 may be silenced in cells of high metastatic potential through epigenetic mechanisms.

Breast cancer is the most common malignancy and a major cause of cancer-related death among Canadian women. Although treatment of primary breast tumours is highly successful through surgery, metastatic breast cancer is difficult to treat. Cancer progression and metastasis require the accumulation of numerous genetic and epigenetic alterations. Normal cells that acquire such alterations can transform into cancer cells, resulting in primary tumour formation. Primary tumours are a heterogeneous population, containing cells of various metastatic potentials. Cells that acquire a high potential for metastasis can spread to secondary locations. Our model system consists of two subpopulations, with different metastatic potential, derived from the same rat mammary adenocarcinoma. Using this model, a differentially expressed novel gene, termed MS-1, was discovered. Due to significant expression of this gene in the poorly metastatic subpopulation and lack of expression in the highly metastatic subpopulation, MS-1 may have involvement in metastasis suppression. Several breast cancer metastasis suppressor genes have been identified on the basis that they are down-regulated during the progression of metastasis. Epigenetic mechanisms, such as DNA methylation, account for loss of expression in several of these genes. Hypermethylation of CpG islands within gene promoters results in deacetylation of histone proteins and produces a compact chromatin structure that is unfavourable for transcription. A CpG island spans the 5 untranslated region, exon 1 and part of intron 1 of the MS-1 gene. Our data reveals aberrant methylation patterns of this CpG island in our model. Also, MS-1 expression appears to be partially induced by both DNA methylation and histone deacetylation inhibitors. Following a screen of several cancer cell lines of various metastatic potential, it appears that the presence of DNA methylation in the CpG island of MS-1 correlates with the lack of MS-1 expression. Therefore, these results suggest that MS-1 may be silenced in cells of high metastatic potential through epigenetic mechanisms.

This work explores the metabolism of mercury in liver and spleen tissue of fish from a methylmercury contaminated wetland. Wild-caught bass, catfish, bowfin and gar were collected. Macrophage centers, which are both reactive and primary germinal centers in various fish tissues, were hypothesized to be the cause of demethylation of methylmercury in fish tissue. Macrophage centers are differentially expressed in fish tissue based on phylogenetic lineage, and are found primarily in the livers of preteleostean fish and in the spleen of teleostean fish. Histology of liver and spleen was examined in both control and wild-caught fish for pathology, size and number of macrophage centers, and for localization of mercury. Total mercury was estimated in the muscle tissue of all fish by direct mercury analysis. Selenium and mercury concentrations were examined in the livers of wild-caught fish by liquid introduction inductively coupled plasma mass spectrometry (ICP-MS). Total mercury was localized in histologic sections by laser ablation ICP-MS (LA-ICP-MS). Mercury speciation was determined for inorganic and methylmercury in liver and spleen of fish by bas chromatography-cold vapor atomic fluorescence spectroscopy (GC-CVAFS). Macrophage center tissue distribution was found to be consistent with the literature, with a predominance of centers in preteleostean liver and in spleens of teleostean fish. Little evidence histopathology was found in the livers or spleens of fish examined, but differences in morphology of macrophage centers and liver tissue across species are noted. the sole sign of liver pathology noted was increased hepatic hemosiderosis in fish with high proportions of liver inorganic mercury. Inorganic mercury was found to predominate in the livers of all fish but bass. Organic mercury was found to predominate in the spleens of all fish. Mercury was found to accumulate in macrophage centers, but concentrations of mercury in this compartment were found to vary less in relation to total mercury than hepatocyte mercury. No association was found between selenium content and inorganic mercury proportions. Overall, findings from this study to not support a primary role for macrophage centers in the demethylation of methylmercury in fish tissues.

Mercury occurs naturally in the environment and is released by human activities. Mercury exists in gaseous, liquid, and solid phases, and all phases are of importance when fate s effects of mercury in terrestrial, fresh and marine water, and atmospheric environments. Mercury can be transformed to a highly toxic form of methylmercury. Humans are exposed to the toxicity of methylmercury by eating fish. Methylmercury is bioaccumulated up the food chain by transfer of residues of methylmercury in smaller organisms that are food for larger organisms in the chain. This sequence of process results in higher concentrations in organisms at higher levels in the food chain with human at the top of the food chain. This study is an evaluation of chemical speciation and biological processes that govern mercury distribution and transformation among three environmental media: atmosphere, water, and sediments. Understanding speciation of mercury and biological processes of methylmercury transformation plays an important part in toxicity and exposure of mercury to living organisms. Speciation also influences transport of mercury within and between environmental media while biological processes of methylmercury transformation influence methylmercury production and its transport to the biological communities. Study also covers the demethylation process that can convert methylmercury to inorganic mercury species. Demethylation and methylation processes therefore may occur in parallel further complicating the assessment of mercury fate in the environment. The study will provide integrated fundamental pathways of mercury species transformation through chemical and biological pathways and will contribute to an understanding of fate and transport of mercury species in environmental media. It will also provide a foundation for a state- and region-wide examination of mercury monitoring and control strategies.

The title chroman is useful in synthesis and as a water-soluble analog of γ-tocopherol, a member of the vitamin E family. This new synthesis of γ-trolox proceeds via selective aromatic demethylation of Trolox, the more easily available 2,5,7,8-tetramethyl homolog compound. This route is shorter than the previous synthesis, avoids the use of cyanide and methoxybutadiene, and requires no chromatography.

INTRODUCTION: Bladder cancer (BC) is highly prevalent. It presents as either non-muscle invasive or muscle-invasive disease. The prognosis of muscle invasive disease is poor, with a 5-year survival rate of less than 50%. Treatment approaches for both types of BC have not advanced much in the last few years and new therapies are needed to overcome the large burden of BC. Recently, a large effort has been undertaken to classify BC into molecular subtypes. These analyses have revealed significant alterations in epigenetic modifiers in BC. A previous study from our group revealed that SH3GL2, a negative regulator of receptor tyrosine kinase (RTK) signaling, was lost with high frequency in BC, leading to increased growth of tumor cells in-vitro and in-vivo. Conversely, forced expression of SH3GL2 in BC cell lines attenuated oncogenic behaviors including growth and migration. In addition to genomic deletion, SH3GL2 is subject to methylation-induced silencing, a key epigenetic mechanism. OBJECTIVE: Epigenetic mechanisms of gene regulation are known to be perturbed in BC. The objectives of this study were to investigate methylation of the SH3GL2 promoter and to test whether agents that promote Deoxyribonucleic acid (DNA) demethylation could be used to re-express SH3GL2 thereby restoring regulation of RTK signaling. METHODS: Methylation of a specific CpG island in the SH3GL2 promoter was analyzed using methylation-specific Polymerase Chain Reaction (PCR) in a panel of BC cell lines with known SH3GL2 messenger Ribonucleic Acid (mRNA) status. Selected BC cell lines were treated with a variety of demethylating agents at different doses and for different times to evoke the re-expression of silenced SH3GL2. Demethylation inhibitors were combined with the histone deacetylase inhibitor, trichostatin A (TSA), to determine whether further re-expression could be achieved. RESULTS: The SH3GL2 promoter displayed differing extents of promoter methylation among cell lines examined. In RT4 cells, the only cell line with detectable expression of SH3GL2 mRNA and protein, the promoter was completely unmethylated. In contrast, T24 and 253J cells displayed significant promoter methylation with little to no SH3GL2 mRNA expressed, consistent with methylation-induced silencing. Treatment of T24 and 253J with 5-Aza-2’-deoxycytidine (5-Aza-dC, 20 M), a DNA methyltransferase (DNMT) inhibitor increased gene expression but this was not dose- or time-dependent. Two additional DNMT inhibitors, Zebularine and RG-108 were also tested. A much higher dosage of Zebularine was required to trigger activation (500 M) while RG-108 was unable to trigger gene reactivation at all. Combination treatment with 5-Aza-dC and TSA further increased SH3GL2 expression compared to either agent alone. These results suggest that DNA methyltransferase inhibition is an effective treatment to re-express SH3GL2 in cells with SH3GL2 promoter silencing. CONCLUSION: The present study shows silencing of SH3GL2 in a variety of BC cell lines as a consequence of DNA promoter hypermethylation. Treatment with demethylating agents was able to increase gene expression. Based on prior findings showing attenuation of tumor cell growth and migration with forced expression of SH3GL2, DNA methyltransferase inhibition represents an effective strategy to re-express SH3GL2 in BC and normalize tumor cell behavior. / 2020-07-03T00:00:00Z

Yes / DNA breaks at protein-coding sequences are well-established threats to tissue homeostasis and maintenance. They arise from the exposure to intracellular and environmental genotoxins, causing damage in one or two strands of the DNA. DNA breaks have been also reported in non-coding regulatory regions such as enhancers and promoters. They arise from essential cellular processes required for gene transcription, cell identity and function. One such process that has attracted recent attention is the oxidative demethylation of DNA and histones, which generates abasic sites and DNA single-strand breaks. Here, we discuss how oxidative DNA breaks at non-coding regulatory regions are generated and the recently reported role of NuMA (nuclear mitotic apparatus) protein in promoting transcription and repair at these regions.

Spray application of 5­azacytidine on established plant seedlings was tested for its demethylating efficiency, as it represents a novel method for plant experimental demethylation with a potentially lower negative impact on plant development compared to the traditional application of the demethytaling agent through germination of seeds in its solution. Further, the 5­azacytidine spray application was used in practice to erase the epigenetic memory in offspring of Taraxacum brevicorniculatum plants from different competitive conditions. The impact of parental competition on the juvenile phenotype was estimated by measuring growth related traits, while the experimental demethylation allowed for evaluating the significance of DNA methylation marks in bioticaly induced transgenerational effects in T. brevirorniculatum.

Shimamoto R, Amano N, Ichisaka T, Watanabe A, Yamanaka S, et al. (2014) Generation and Characterization of Induced Pluripotent Stem Cells from Aid-Deficient Mice. PLoS ONE 9(4): e94735. doi:10.1371/journal.pone.0094735 / 京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第18515号 / 医科博第56号 / 新制||医科||4(附属図書館) / 31401 / 京都大学大学院医学研究科医科学専攻 / (主査)教授 斎藤 通紀, 教授 平家 俊男, 教授 山田 泰広 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20195号 / 理博第4280号 / 新制||理||1615(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 杉山 弘, 教授 三木 邦夫, 教授 秋山 芳展 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM