178 research outputs found

    Seaweed extract as a biostimulant for legume crop, green gram

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    The aim of this research is to investigate the effect of seaweed extracts obtained from the marine green algae, Ulva lactuca Linnaeus, Caulerpa scalpelliformis (R. Brown ex Turner) C. Agardh, brown algae Sargassum plagiophyllum C. Agardh, Turbinaria conoides (J. Agardh) Kutzing, Padina tetrastromatica Hauck, Dictyota dichotama (Hudson) J. V. Lamouroux on the stimulate germination, growth parameters of the Vigna radiata. The present study reveals the seeds germination, fresh weight and dry weight of shoots and roots. These results suggested that seaweed extracts stronger induce seed germination and growth parameters

    Sodium-coupled Monocarboxylate Transporters in Normal Tissues and in Cancer

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    SLC5A8 and SLC5A12 are sodium-coupled monocarboxylate transporters (SMCTs), the former being a high-affinity type and the latter a low-affinity type. Both transport a variety of monocarboxylates in a Na+-coupled manner. They are expressed in the gastrointestinal tract, kidney, thyroid, brain, and retina. SLC5A8 is localized to the apical membrane of epithelial cells lining the intestinal tract and proximal tubule. In the brain and retina, its expression is restricted to neurons and the retinal pigment epithelium. The physiologic functions of SLC5A8 include absorption of short-chain fatty acids in the colon and small intestine, reabsorption of lactate and pyruvate in the kidney, and cellular uptake of lactate and ketone bodies in neurons. It also transports the B-complex vitamin nicotinate. SLC5A12 is also localized to the apical membrane of epithelial cells lining the intestinal tract and proximal tubule. In the brain and retina, its expression is restricted to astrocytes and Müller cells. SLC5A8 also functions as a tumor suppressor; its expression is silenced in tumors of colon, thyroid, stomach, kidney, and brain. The tumor-suppressive function is related to its ability to mediate concentrative uptake of butyrate, propionate, and pyruvate, all of which are inhibitors of histone deacetylases. SLC5A8 can also transport a variety of pharmacologically relevant monocarboxylates, including salicylates, benzoate, and γ-hydroxybutyrate. Non-steroidal anti-inflammatory drugs such as ibuprofen, ketoprofen, and fenoprofen, also interact with SLC5A8. These drugs are not transportable substrates for SLC5A8, but instead function as blockers of the transporter. Relatively less is known on the role of SLC5A12 in drug transport

    Key stages in mammary gland development - Involution: apoptosis and tissue remodelling that convert the mammary gland from milk factory to a quiescent organ

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    Involution of the mammary gland is an essential process that removes the milk-producing epithelial cells when they become redundant at weaning. It is a two-step process that involves the death of the secretory epithelium and its replacement by adipo-cytes. During the first phase, remodelling is inhibited and apoptotic cells can be seen in the lumena of the alveoli. In the second phase, apoptosis is accompanied by remodelling of the surrounding stroma and re-differentiation of the adipocytes. Considerable effort has been directed towards understanding the molecular mechanisms of the involution process and this has resulted in the identification of the principal signalling pathways involved

    Molecular targets for the protodynamic action of cis-urocanic acid in human bladder carcinoma cells

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    <p>Abstract</p> <p>Background</p> <p>cis-urocanic acid (cis-UCA) is an endogenous amino acid metabolite capable of transporting protons from the mildly acidic extracellular medium into the cell cytosol. The resulting intracellular acidification suppresses many cellular activities. The current study was aimed at characterizing the molecular mechanisms underlying cis-UCA-mediated cytotoxicity in cultured cancer cells.</p> <p>Methods</p> <p>5367 bladder carcinoma cells were left untreated or treated with cis-UCA. Cell death was assessed by measuring caspase-3 activity, mitochondrial membrane polarization, formation and release of cytoplasmic histone-associated DNA fragments, and cellular permeabilization. Cell viability and metabolic activity were monitored by colorimetric assays. Nuclear labelling was used to quantify the effects of cis-UCA on cell cycle. The activity of the ERK and JNK signalling pathways was studied by immunoblotting with specific antibodies. Phosphatase activity in cis-UCA-treated cells was determined by assay kits measuring absorbance resulting from the dephosphorylation of an artificial substrate. All statistical analyses were performed using the two-way Student's t-test (p < 0.05).</p> <p>Results</p> <p>Here we report that treatment of the 5637 human bladder carcinoma cells with 2% cis-UCA induces both apoptotic and necrotic cell death. In addition, metabolic activity of the 5637 cells is rapidly impaired, and the cells arrest in cell cycle in response to cis-UCA. Importantly, we show that cis-UCA promotes the ERK and JNK signalling pathways by efficiently inhibiting the activity of serine/threonine and tyrosine phosphatases.</p> <p>Conclusions</p> <p>Our studies elucidate how cis-UCA modulates several cellular processes, thereby inhibiting the proliferation and survival of bladder carcinoma cells. These anti-cancer effects make cis-UCA a potential candidate for the treatment of non-muscle invasive bladder carcinoma.</p

    An integrative approach to identifying cancer chemoresistance-associated pathways

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    <p>Abstract</p> <p>Background</p> <p>Resistance to chemotherapy severely limits the effectiveness of chemotherapy drugs in treating cancer. Still, the mechanisms and critical pathways that contribute to chemotherapy resistance are relatively unknown. This study elucidates the chemoresistance-associated pathways retrieved from the integrated biological interaction networks and identifies signature genes relevant for chemotherapy resistance.</p> <p>Methods</p> <p>An integrated network was constructed by collecting multiple metabolic interactions from public databases and the k-shortest path algorithm was implemented to identify chemoresistant related pathways. The identified pathways were then scored using differential expression values from microarray data in chemosensitive and chemoresistant ovarian and lung cancers. Finally, another pathway database, Reactome, was used to evaluate the significance of genes within each filtered pathway based on topological characteristics.</p> <p>Results</p> <p>By this method, we discovered pathways specific to chemoresistance. Many of these pathways were consistent with or supported by known involvement in chemotherapy. Experimental results also indicated that integration of pathway structure information with gene differential expression analysis can identify dissimilar modes of gene reactions between chemosensitivity and chemoresistance. Several identified pathways can increase the development of chemotherapeutic resistance and the predicted signature genes are involved in drug resistant during chemotherapy. In particular, we observed that some genes were key factors for joining two or more metabolic pathways and passing down signals, which may be potential key targets for treatment.</p> <p>Conclusions</p> <p>This study is expected to identify targets for chemoresistant issues and highlights the interconnectivity of chemoresistant mechanisms. The experimental results not only offer insights into the mode of biological action of drug resistance but also provide information on potential key targets (new biological hypothesis) for further drug-development efforts.</p

    The effects of aromatase inhibitors on lipids and thrombosis

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    Oestrogen is known to influence blood lipid levels and though its cardioprotective effects are less clear than once thought, there remains concern that reduction of oestrogen levels during hormonal treatment for breast cancer may have an adverse effect on cardiovascular risk. While tamoxifen has been shown to improve lipid profiles, the aromatase inhibitors have a very different mode of action and do not possess the oestrogen-agonistic effects of tamoxifen. At present, there are few data on the effects of these agents on lipid profiles. Available data are mixed, but suggest that the different aromatase inhibitors have different effects on lipid profiles. Some studies show anastrozole as generally having little effect on lipids, while others have indicated adverse effects on lipid profiles/increased hypercholesterolaemia. Letrozole has been associated with adverse effects on lipid profiles in some studies, including BIG 1-98, but short-term data from randomised trials do not show increased cardiovascular morbidity. By contrast, exemestane, which has been studied in slightly more detail, may either have little effect or may be associated with slightly improved lipid profiles. In general, the changes have been small and are likely to be of little relevance in women with advanced breast cancer, but if these agents come to be used in early breast cancer, their impact on lipid profiles may become more important. Many studies are currently underway with the aromatase inhibitors, with safety assessments including monitoring lipid levels. The results of these studies are keenly awaited

    Lineage-Specific Restraint of Pituitary Gonadotroph Cell Adenoma Growth

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    Although pituitary adenomas are usually benign, unique trophic mechanisms restraining cell proliferation are unclear. As GH-secreting adenomas are associated with p53/p21-dependent senescence, we tested mechanisms constraining non-functioning pituitary adenoma growth. Thirty six gonadotroph-derived non-functioning pituitary adenomas all exhibited DNA damage, but undetectable p21 expression. However, these adenomas all expressed p16, and >90% abundantly expressed cytoplasmic clusterin associated with induction of the Cdk inhibitor p15 in 70% of gonadotroph and in 26% of somatotroph lineage adenomas (p = 0.006). Murine LβT2 and αT3 gonadotroph pituitary cells, and αGSU.PTTG transgenic mice with targeted gonadotroph cell adenomas also abundantly expressed clusterin and exhibited features of oncogene-induced senescence as evidenced by C/EBPβ and C/EBPδ induction. In turn, C/EBPs activated the clusterin promoter ∼5 fold, and elevated clusterin subsequently elicited p15 and p16 expression, acting to arrest murine gonadotroph cell proliferation. In contrast, specific clusterin suppression by RNAis enhanced gonadotroph proliferation. FOXL2, a tissue-specific gonadotroph lineage factor, also induced the clusterin promoter ∼3 fold in αT3 pituitary cells. As nine of 12 pituitary carcinomas were devoid of clusterin expression, this protein may limit proliferation of benign adenomatous pituitary cells. These results point to lineage-specific pathways restricting uncontrolled murine and human pituitary gonadotroph adenoma cell growth

    Mammary Involution and Breast Cancer Risk: Transgenic Models and Clinical Studies

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    Postlactational involution is the process following weaning during which the mammary gland undergoes massive cell death and tissue remodeling as it returns to the pre-pregnant state. Lobular involution is the process by which the breast epithelial tissue is gradually lost with aging of the mammary gland. While postlactational involution and lobular involution are distinct processes, recent studies have indicated that both are related to breast cancer development. Experiments using a variety of rodent models, as well as observations in human populations, suggest that deregulation of postlactational involution may act to facilitate tumor formation. By contrast, new human studies show that completion of lobular involution protects against subsequent breast cancer incidence

    Defining the Molecular Basis of Tumor Metabolism: a Continuing Challenge Since Warburg's Discovery

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    Cancer cells are the product of genetic disorders that alter crucial intracellular signaling pathways associated with the regulation of cell survival, proliferation, differentiation and death mechanisms. the role of oncogene activation and tumor suppressor inhibition in the onset of cancer is well established. Traditional antitumor therapies target specific molecules, the action/expression of which is altered in cancer cells. However, since the physiology of normal cells involves the same signaling pathways that are disturbed in cancer cells, targeted therapies have to deal with side effects and multidrug resistance, the main causes of therapy failure. Since the pioneering work of Otto Warburg, over 80 years ago, the subversion of normal metabolism displayed by cancer cells has been highlighted by many studies. Recently, the study of tumor metabolism has received much attention because metabolic transformation is a crucial cancer hallmark and a direct consequence of disturbances in the activities of oncogenes and tumor suppressors. in this review we discuss tumor metabolism from the molecular perspective of oncogenes, tumor suppressors and protein signaling pathways relevant to metabolic transformation and tumorigenesis. We also identify the principal unanswered questions surrounding this issue and the attempts to relate these to their potential for future cancer treatment. As will be made clear, tumor metabolism is still only partly understood and the metabolic aspects of transformation constitute a major challenge for science. Nevertheless, cancer metabolism can be exploited to devise novel avenues for the rational treatment of this disease. Copyright (C) 2011 S. Karger AG, BaselFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Fed ABC UFABC, CCNH, Santo Andre, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ciencias Biol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, São Paulo, BrazilUniv Fed Sao Carlos UFSCar, DFQM, Sorocaba, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Ciencias Biol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Bioquim, São Paulo, BrazilFAPESP: 10/16050-9FAPESP: 10/11475-1FAPESP: 08/51116-0Web of Scienc

    MCT1-mediated transport of a toxic molecule is an effective strategy for targeting glycolytic tumors

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    There is increasing evidence that oncogenic transformation modifies the metabolic program of cells. A common alteration is the upregulation of glycolysis, and efforts to target glycolytic enzymes for anticancer therapy are under way. Here, we performed a genome-wide haploid genetic screen to identify resistance mechanisms to 3-bromopyruvate (3-BrPA), a drug candidate that inhibits glycolysis in a poorly understood fashion. We identified the SLC16A1 gene product, MCT1, as the main determinant of 3-BrPA sensitivity. MCT1 is necessary and sufficient for 3-BrPA uptake by cancer cells. Additionally, SLC16A1 mRNA levels are the best predictor of 3-BrPA sensitivity and are most elevated in glycolytic cancer cells. Furthermore, forced MCT1 expression in 3-BrPA–resistant cancer cells sensitizes tumor xenografts to 3-BrPA treatment in vivo. Our results identify a potential biomarker for 3-BrPA sensitivity and provide proof of concept that the selectivity of cancer-expressed transporters can be exploited for delivering toxic molecules to tumors.National Institutes of Health (U.S.) (NIH CA103866)Jane Coffin Childs Memorial Fund for Medical Research (Fellowship)National Science Foundation (U.S.) (Fellowship)Howard Hughes Medical Institute (Investigator
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