Abstract. Constitutive activation of nuclear factor-κB (NF-κB) stimulates cell proliferation and metastasis, and inhibits apoptosis in breast cancer. Transforming growth factor-β (TGF-β) signaling pathway is deregulated in breast cancer progression and metastasis. The aim of the present study was to investigate the inhibitory effects of the two small leucine rich proteoglycans fibromodulin (Fmod) and decorin (Dcn), overexpressed using adenovirus gene transfer, on NF-κB-activity and TGF-β1-expression in the highly metastatic 4T1 breast cancer cell line. The results demonstrate that Fmod and Dcn overexpression is associated with NF-κB and TGF-β1 downregulation, and that Fmod promotes this effect more effectively compared with Dcn.

Mammalian phosphatidic acid phosphatases, also called lipins, show high amino acid sequence identity to Saccharomyces cerevisiae Pah1p and catalyze the dephosphorylation of phosphatidic acid (PA) to diacylglycerol. Both the substrate and product of the reaction are key precursors for the synthesis of phospholipids and triacylglycerol (TAG). We now show that expression of the Trypanosoma brucei lipin homolog TbLpn is essential for parasite survival in culture. Inducible down-regulation of TbLpn in T. brucei procyclic forms increased cellular PA content, decreased the numbers of lipid droplets, reduced TAG steady-state levels and inhibited in vivo [ H]TAG formation after labeling trypanosomes with [ H]glycerol. In addition, fluorescence and transmission electron microscopy revealed that depletion of TbLpn caused major alterations in mitochondrial morphology and function, i.e., the appearance of distorted mitochondrial matrix, and reduced ATP production via oxidative phosphorylation. Effects of lipin depletion on mitochondrial integrity have previously not been reported. N- and C-terminally tagged forms of TbLpn were localized in the cytosol.

Sphingosine-1-phosphate is a signaling molecule involved in the control of cell migration, differentiation, survival and other physiological processes. This sphingolipid metabolite can be degraded by the action of sphingosine-1-phosphate lyase (SPL) to form hexadecenal and ethanolamine phosphate. The importance of SPL-mediated ethanolamine phosphate formation has been characterized in only few cell types. We show that in the protozoan parasite Trypanosoma brucei, expression of TbSpl is essential for cell survival. Ablation of TbSpl expression increased sphingosine-1-phosphate levels and reduced de novo formation and steady-state levels of the glycerophospholipid phosphatidylethanolamine (PE). Growth of TbSpl-depleted parasites could be in part rescued by ethanolamine supplementation to the growth medium, indicating that the main function of TbSpl is to provide ethanolamine phosphate for PE synthesis. In contrast to most cell types analyzed, where SPL localizes to the endoplasmic reticulum, we found by high-resolution microscopy that TbSpl is a mitochondrial protein. In spite of its mitochondrial localization, TbSpl depletion had no apparent effect on mitochondrial morphology but resulted in aggregation of acidocalcisomes. Our results link mitochondria to sphingolipid metabolism and suggest possible roles for PE in acidocalcisome function. Sphingosine-1-phosphate (S1P) is a sphingolipid metabolite involved in the control of cell migration, differentiation and survival, as well as numerous other (patho-)physiological processes (reviewed in 1-5). S1P levels are regulated through the actions of three enzyme activities: i) sphingosine kinase synthesizes S1P by phosphorylating the long chain base sphingosine, ii) sphingosine phosphohydrolases catalyze the reverse reaction to produce sphingosine, and iii) sphingosine-1-phosphate lyase (SPL) irreversibly degrades S1P by cleaving the acyl chain between carbon atoms 2 and 3, resulting in the formation of hexadecenal and ethanolamine phosphate (reviewed in 3,6). Ethanolamine phosphate, in turn, may represent a substrate for phosphatidylethanolamine (PE) synthesis by the CDP-ethanolamine branch of the Kennedy pathway 7. SPL is dependent on pyridoxal 5′-phosphate as cofactor for enzymatic activity 8. In mammals and yeast, SPL is membrane-bound via a single N-terminal transmembrane domain, which is not strictly required for in vitro enzyme activity 9,10. In contrast, at least in Saccharomyces cerevisiae, the transmembrane domain is necessary for SPL activity in vivo and may be involved in oligomer formation 10. The structure has been solved for bacterial SPL homologues 11-13 and soluble forms of human 9,14 and yeast 11 SPL. Cytosolically produced S1P can be secreted into the extracellular environment via specific transporters (reviewed in 6), where it binds to cell surface G protein-coupled receptors, known in mammals as S1PR 1-5 (reviewed by 15-17), to induce numerous cellular and tissue-specific responses. Alternatively, S1P can act as

Background:β-thalassemia is one of the most widespread diseases in the world, including Iran. In this study, we reported, for the first time, a 290-bp β-globin gene deletion in the south of Iran.Methods:Four individuals from three unrelated families with Arabic ethnic background were studied in Khuzestan Province. Red blood cell indices and hemoglobin analysis were carried out according to the standard methods. Genomic DNA was obtained from peripheral blood cells by salting out procedures. β-globin gene amplification, multiplex ligation-dependent probe amplification (MLPA), and DNA sequencing were performed.Results:The PCR followed by sequencing and MLPA test of the β-globin gene confirmed the presence of a 290-bp deletion in the heterozygous form, along with -88C>A mutation. All the individuals had elevated hemoglobin A2 and normal fetal hemoglobin levels.Conclusions:This mutation causes β0-thalassemia and can be highly useful for prenatal diagnosis in compound heterozygous condition with different β-globin gene mutations.