103,471 research outputs found
Internal circle uplifts, transversality and stratified G-structures
No full textWe study stratied G-structures in N = 2 compactications of M-theory on eightmanifolds
M using the uplift to the auxiliary nine-manifold ^M = M S1. We show that the
cosmooth generalized distribution ^D on ^M which arises in this formalism may have pointwise
transverse or non-transverse intersection with the pull-back of the tangent bundle of M, a fact
which is responsible for the subtle relation between the spinor stabilizers arising on M and ^M
and for the complicated stratied G-structure on M which we uncovered in previous work. We
give a direct explanation of the latter in terms of the former and relate explicitly the dening
forms of the SU(2) structure which exists on the generic locus U of M to the dening forms of
the SU(3) structure which exists on an open subset ^ U of ^M , thus providing a dictionary between
the eight- and nine-dimensional formalisms.101sciescopu
Principles of MicroRNA Involvement in Breast Cancer
No full textEditorial on the role of microRNAs in breast cancer
The landscape of G-structures in eight-manifold compactifications of M-theory
No full textWe consider spaces of "virtual" constrained generalized Killing spinors, i.e. spaces of Majorana spinors which correspond to "off-shell" s-extended supersymmetry in compactifications of eleven-dimensional supergravity based on eight-manifolds M. Such spaces naturally induce two stratifications of M, called the chirality and stabilizer stratification. For the case s = 2, we describe the former using the canonical Whitney stratification of a three-dimensional semi-algebraic set R. We also show that the stabilizer stratification coincides with the rank stratification of a cosmooth generalized distribution D-0 and describe it explicitly using the Whitney stratification of a four-dimensional semi-algebraic set B. The stabilizer groups along the strata are isomorphic with SU(2), SU(3), G(2) or SU(4), where SU(2) corresponds to the open stratum, which is generically non-empty. We also determine the rank stratification of a larger generalized distribution D which turns out to be integrable in the case of compactifications down to AdS(3). Open Access, (c) The Authors.1111sciescopu
Breast cancer metastasis: a microRNA story
No full textMicroRNAs (miRNAs) are small noncoding RNAs with regulatory functions, which play an important role in breast cancer. Several studies have shown that miRNAs can act either as tumor suppressors or as oncogenes, and that measurement of miRNA expression in malignancies may have diagnostic and prognostic implications. This article highlights a series of three recent studies that prove the involvement of miRNAs in breast cancer metastases. The first proves that miR-10b indirectly activates the pro-metastatic gene RHOC by suppressing HOXD10, thus leading to tumor invasion and metastasis. The second proves that miR-373 and miR-520c can also promote tumor invasion and metastasis, at least in part by regulating the gene CD44. The third identifies miR-335, miR-206, and miR-126 as suppressors of breast cancer metastasis. Loss of miR-335 leads to the activation of SOX4 and TNC (encoding tenascin C), which are responsible for the acquisition of metastatic properties. Altogether, these remarkable findings are important for our understanding of malignant transformation in the breast and may have implications for the management of patients with advanced breast cancer. The use of miRNAs as anticancer therapeutic agents is promising, and such fine molecular studies certainly help in bringing miRNAs closer to clinical practice
Involvement of MicroRNAs in Human Cancer: Discovery and Expression Profiling
No full textThe expression of microRNAs (miRNAs) is deregulated in human cancer, with some miRNAs consistently up- or down-regulated in more than one type of neoplasm. The demonstration that aberrantly expressed miRNAs can affect the function of known oncogenes and tumor suppressor genes established molecular links with pathways implicated in malignant transformation. Cell cycle progression, loss of differentiation, increased survival, invasion, and metastasis were shown to be all under the influence of miRNAs, thereby implicating that miRNAs can themselves act as oncogenes or tumor suppressor genes. Besides increasing our knowledge on the molecular basis of cancer, accumulating evidences indicate that miRNA expression profiling has the potential of being translated into clinical applications. Analysis of cancer tissues revealed that miRNAs could be molecular markers useful for cancer classification, prognostic stratification, and drug-response prediction. MiRNAs also emerged as circulating markers, which may become valuable for early diagnosis and follow-up investigations. If we consider that studies on miRNAs in cancer therapy have already produced important results, in just few years, miRNAs have had a great impact in all cancer areas. Whether this will translate into important clinical applications is still too early to say
Expression profiles of micro RNA in proliferating and differentiating 32D murine myeloid cells
No full text32D cells are murine myeloid cells that grow indefinitely in Interleukin-3 (IL-3). In these cells, the type 1 insulin-like growth factor (IGF-I) and granulocytic-colony stimulating factor (G-CSF) induce differentiation to granulocytes. 32D cells do not express insulin receptor substrate-1 (IRS-1) or IRS-2, docking proteins of the IGF-I receptor. Ectopic expression of IRS-1 in these cells inhibits differentiation, the cells become IL-3 independent and IGF-1 dependent and can form tumors in mice. 32D and 32D-derived cells offer a good model in which to study the expression profiles of Micro Rna (miR) related to sustained proliferation or differentiation. We present here the data obtained with miR micro-arrays and identify the miR that are regulated by IGF-1 or G-CSF and are associated with either differentiation or indefinite cell proliferation of 32D murine myeloid cells
Chromosomal rearrangements and microRNAs: A new cancer link with clinical implications
No full textThere is widespread aberrant expression of mature and/or precursor microRNAs in cancer cells, as microRNAs are deregulated consequent to chromosomal alterations and other genomic abnormalities. The identification of such abnormalities has a clear diagnostic and prognostic significance, and there are ever increasing examples of links between certain human cancers and modifications at microRNA loci
microRNAs and cancer – new paradigms in molecular oncology
No full textThe “classic” view of molecular oncology indicates that cancer is a genetic disease involving tumor suppressor and oncogenic proteins. However, in the recent years, it has been demonstrated that small regulatory non-coding RNAs (ncRNAs) named microRNAs (miRNAs) are involved in human tumorigenesis, thus revealing a new layer in the molecular architecture of human cancer. Gene expression studies revealed that hundreds of miRNAs are deregulated in cancer cells and functional studies clarified that miRNAs are involved in all the molecular and biological processes that drive tumorigenesis. Here, we summarize the recent advances in miRNA involvement in human cancer and illustrate the benefits of using these knowledge for medical practice. New diagnostic classifiers based on miRNAs will soon be available for medical practitioners and, even more importantly, miRNAs may become novel anti-cancer tools
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