[Regulation of human β-1,4-galactosyltransferase V gene expression in cancer cells]

Central Role of β-1,4-GalT-V in Cancer Signaling, Inflammation, and Other Disease-Centric Pathways

UDP-Galactose: Glucosylceramide, β-1,4-Galactose transferase-V (β-1,4-GalT-V), is a member of a large glycosyltransferase family, primarily involved in the transfer of sugar residues from nucleotide sugars, such as galactose, glucose mannose, etc., to sugar constituents of glycosphingolipids and glycoproteins. For example, UDP-Galactose: Glucosylceramide, β-1,4-galactosyltransferase (β-1,4-GalT-V), transfers galactose to glucosylceramide to generate Lactosylceramide (LacCer), a bioactive "lipid second messenger" that can activate nicotinamide adenine dinucleotide phosphate(NADPH) oxidase (NOX-1) to produce superoxide's (O2-) to activate several signaling pathways critical in regulating multiple phenotypes implicated in health and diseases. LacCer can also activate cytosolic phospholipase A-2 to produce eicosanoids and prostaglandins to induce inflammatory pathways. However, the lack of regulation of β-1,4-GalT-V contributes to critical phenotypes central to cancer and cardiovascular diseases, e.g., cell proliferation, migration, angiogenesis, phagocytosis, and apoptosis. Additionally, inflammation that accompanies β-1,4-GalT-V dysregulation accelerates the initiation and progression of cancer, cardiovascular diseases, as well as inflammation-centric diseases, like lupus erythematosus, chronic obstructive pulmonary disease (COPD), and inflammatory bowel diseases. An exciting development in this field of research arrived due to the recognition that the activation of β-1,4-GalT-V is a "pivotal" point of convergence for multiple signaling pathways initiated by physiologically relevant molecules, e.g., growth factors, oxidized-low density lipoprotein(ox- LDL), pro-inflammatory molecules, oxidative and sheer stress, diet, and cigarette smoking. Thus, dysregulation of these pathways may well contribute to cancer, heart disease, skin diseases, and several inflammation-centric diseases in experimental animal models of human diseases and in humans. These observations have been described under post-transcriptional modifications of β-1,4- GalT-V. On the other hand, we also point to the important role of β-1-4 GalT-V-mediated glycosylation in altering the formation of glycosylated precursor forms of proteins and their activation, e.g., β-1 integrin, wingless-related integration site (Wnt)/-β catenin, Frizzled-1, and Notch1. Such alterations in glycosylation may influence cell differentiation, angiogenesis, diminished basement membrane architecture, tissue remodeling, infiltrative growth, and metastasis in human colorectal cancers and breast cancer stem cells. We also discuss Online Mendelian Inheritance in Man (OMIM), which is a comprehensive database of human genes and genetic disorders used to provide information on the genetic basis of inherited diseases and traits and information about the molecular pathways and biological processes that underlie human physiology. We describe cancer genes interacting with the β-1,4-GalT-V gene and homologs generated by OMIM. In sum, we propose that β-1,4-GalT-V gene/protein serves as a "gateway" regulating several signal transduction pathways in oxidative stress and inflammation leading to cancer and other diseases, thus rationalizing further studies to better understand the genetic regulation and interaction of β-1,4-GalT-V with other genes. Novel therapies will hinge on biochemical analysis and characterization of β-1,4-GalT-V in patient-derived materials and animal models. And using β-1,4-GalT-V as a "bonafide drug target" to mitigate these diseases.

Genomic analysis of clonal eosinophils by CGH arrays reveals new genetic regions involved in chronic eosinophilia

To assess the presence of genetic imbalances in patients with myeloproliferative neoplasms (MPNs), 38 patients with chronic eosinophilia were studied by array comparative genomic hybridization (aCGH): seven had chronic myelogenous leukaemia (CML), BCR-ABL1 positive, nine patients had myeloproliferative neoplasia Ph- (MPN-Ph-), three had a myeloid neoplasm associated with a PDGFRA rearrangement, and the remaining two cases were Lymphoproliferative T neoplasms associated with eosinophilia. In addition, 17 patients had a secondary eosinophilia and were used as controls. Eosinophilic enrichment was carried out in all cases. Genomic imbalances were found in 76% of all MPN patients. Losses on 20q were the most frequent genetic abnormality in MPNs (32%), affected the three types of MPN studied. This study also found losses at 11q13.3 in 26% of patients with MPN-Ph- and in 19p13.11 in two of the three patients with an MPN associated with a PDGFRA rearrangement. In addition, 29% of patients with CML had losses on 8q24. In summary, aCGH revealed clonality in eosinophils in most MPNs, suggesting that it could be a useful technique for defining clonality in these diseases. The presence of genetic losses in new regions could provide new insights into the knowledge of these MPN associated with eosinophilia.