Mechanisms of silencing the breast tumor suppressor gene single-minded 2

In order to design patient-tailored medicine and better predict patient response totreatment and outcome, the mechanisms of altered gene expression in cancer cells mustbe understood. Recently, Single-minded 2 (SIM2) has been shown to be a breast tumorsuppressor gene that is down-regulated in approximately 72% of breast cancers, andreintroduction of SIM2 into highly metastatic cancer cells decreases their proliferativerate and their ability to grow on soft agar. SIM2 is a member of the basic helix-loophelixPer-Arnt-Sim (bHLH/PAS) family of transcription factors, which includes genesresponsible for maintenance of circadian rhythms (CLOCK and BMAL) and for sensinghypoxia (HIF-a) and environmental contaminants (AHR). Here we have shown thatSIM2 undergoes progressive epigenetic changes that correlate with loss of expressionduring breast cancer progression in a cell line model. In addition, NFB, C/EBPb andthe Notch intracellular domain (NICD) act as repressors of SIM2 transcription. Each isable to bind to the SIM2 promoter, demonstrated by chromatin immunoprecipitationassay, with the NICD acting through a novel CBF1-independent mechanism. NFB is acentral mediator of SIM2 regulation as it facilitates repression by C/EBPb and leads to deacetylation of histone 3 associated with the SIM2 promoter, contributing to epigeneticchanges observed during cancer progression. SIM2, however, also antagonizes NFBsignaling through inhibiting specific NFB target genes including the ATP-bindingcassette transporter, ABCB5, and through direct interaction with NFB. SIM2, throughthis antagonism of NFB, increases cancer cell susceptibility to antineoplastic drugs,including doxorubicin and 5-fluorouracil

Loss of Singleminded-2s in the Mouse Mammary Gland Induces an Epithelial-Mesenchymal Transition Associated with Up-Regulation of Slug and Matrix Metalloprotease 2

The short splice variant of the basic helix-loop-helix Per-Arnt-Sim transcription factor Singleminded-2, SIM2s, has been implicated in development and is frequently lost or reduced in primary breast tumors. Here, we show that loss of Sim2s causes aberrant mouse mammary gland ductal development with features suggestive of malignant transformation, including increased proliferation, loss of polarity, down-regulation of E-cadherin, and invasion of the surrounding stroma. Additionally, knockdown of SIM2s in MCF-7 breast cancer cells contributed to an epithelial-mesenchymal transition (EMT) and increased tumorigenesis. In both Sim2(−/−) mammary glands and SIM2s-depleted MCF7 cells, these changes were associated with increased SLUG and MMP2 levels. SIM2s protein was detectable on the SLUG promoter, and overexpression of SIM2s repressed expression from a SLUG-controlled reporter in a dose-dependent manner. To our knowledge, SIM2s is the first protein shown to bind and repress the SLUG promoter, providing a plausible explanation for the development role and breast tumor-suppressive activity of SIM2s. Together, our results suggest that SIM2s is a key regulator of mammary-ductal development and that loss of SIM2s expression is associated with an invasive, EMT-like phenotype

The Promoter of Rv0560c Is Induced by Salicylate and Structurally-Related Compounds in Mycobacterium tuberculosis

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), is a major global health threat. During infection, bacteria are believed to encounter adverse conditions such as iron depletion. Mycobacteria synthesize iron-sequestering mycobactins, which are essential for survival in the host, via the intermediate salicylate. Salicylate is a ubiquitous compound which is known to induce a mild antibiotic resistance phenotype. In M. tuberculosis salicylate highly induces the expression of Rv0560c, a putative methyltransferase. We identified and characterized the promoter and regulatory elements of Rv0560c. PRv0560c activity was highly inducible by salicylate in a dose-dependent manner. The induction kinetics of PRv0560c were slow, taking several days to reach maximal activity, which was sustained over several weeks. Promoter activity could also be induced by compounds structurally related to salicylate, such as aspirin or para-aminosalicylic acid, but not by benzoate, indicating that induction is specific to a structural motif. The −10 and −35 promoter elements were identified and residues involved in regulation of promoter activity were identified in close proximity to an inverted repeat spanning the −35 promoter element. We conclude that Rv0560c expression is controlled by a yet unknown repressor via a highly-inducible promoter

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

Background: Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions. Results: A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Conclusions: The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine

Mechanisms of silencing the breast tumor suppressor gene single-minded 2

In order to design patient-tailored medicine and better predict patient response totreatment and outcome, the mechanisms of altered gene expression in cancer cells mustbe understood. Recently, Single-minded 2 (SIM2) has been shown to be a breast tumorsuppressor gene that is down-regulated in approximately 72% of breast cancers, andreintroduction of SIM2 into highly metastatic cancer cells decreases their proliferativerate and their ability to grow on soft agar. SIM2 is a member of the basic helix-loophelixPer-Arnt-Sim (bHLH/PAS) family of transcription factors, which includes genesresponsible for maintenance of circadian rhythms (CLOCK and BMAL) and for sensinghypoxia (HIF-a) and environmental contaminants (AHR). Here we have shown thatSIM2 undergoes progressive epigenetic changes that correlate with loss of expressionduring breast cancer progression in a cell line model. In addition, NFB, C/EBPb andthe Notch intracellular domain (NICD) act as repressors of SIM2 transcription. Each isable to bind to the SIM2 promoter, demonstrated by chromatin immunoprecipitationassay, with the NICD acting through a novel CBF1-independent mechanism. NFB is acentral mediator of SIM2 regulation as it facilitates repression by C/EBPb and leads to deacetylation of histone 3 associated with the SIM2 promoter, contributing to epigeneticchanges observed during cancer progression. SIM2, however, also antagonizes NFBsignaling through inhibiting specific NFB target genes including the ATP-bindingcassette transporter, ABCB5, and through direct interaction with NFB. SIM2, throughthis antagonism of NFB, increases cancer cell susceptibility to antineoplastic drugs,including doxorubicin and 5-fluorouracil

Enigmazole Phosphomacrolides from the Marine Sponge Cinachyrella enigmatica

Enigmazole B (1) and four new analogues, cis-enigmazole B (2), dehydroenigmazole B (3), enigmimide B (4), and enigmimide A (5), were isolated from the marine sponge Cinachyrella enigmatica. Their planar structures were elucidated by detailed NMR and MS data analyses, which established 1–3 to be oxazole-substituted 18-membered phosphomacrolides, while 4 and 5 were oxazole ring-opened congeners. The relative and absolute configurations in 1 were determined by a combination of chemical transformations and spectroscopic analyses. Photooxidation of the oxazole moiety in 1 gave enigmimide B (4), thus establishing that 4 has the same absolute configuration of 1. Enigmazole B (1) along with analogues 2 and 3 showed cytotoxicity against murine IC-2 mast cells with IC50 values of 3.6–7.0 μM. The enigmimides (4 and 5) and dephosphoenigmazoles did not show cytotoxicity (IC50 > 10 μM), implying that both the oxazole moiety and the phosphate group are necessary for the cytotoxicity of the enigmazole class macrolides

A Genomic Approach to Delineating the Occurrence of Scoliosis in Arthrogryposis Multiplex Congenita

Arthrogryposis multiplex congenita (AMC) describes a group of conditions characterized by the presence of non-progressive congenital contractures in multiple body areas. Scoliosis, defined as a coronal plane spine curvature of ≥10 degrees as measured radiographically, has been reported to occur in approximately 20% of children with AMC. To identify genes that are associated with both scoliosis as a clinical outcome and AMC, we first queried the DECIPHER database for copy number variations (CNVs). Upon query, we identified only two patients with both AMC and scoliosis (AMC-SC). The first patient contained CNVs in three genes (FBN2, MGF10, and PITX1), while the second case had a CNV in ZC4H2. Looking into small variants, using a combination of Human Phenotype Ontogeny and literature searching, 908 genes linked with scoliosis and 444 genes linked with AMC were identified. From these lists, 227 genes were associated with AMC-SC. Ingenuity Pathway Analysis (IPA) was performed on the final gene list to gain insight into the functional interactions of genes and various categories. To summarize, this group of genes encompasses a diverse group of cellular functions including transcription regulation, transmembrane receptor, growth factor, and ion channels. These results provide a focal point for further research using genomics and animal models to facilitate the identification of prognostic factors and therapeutic targets for AMC