72 research outputs found

    SLC5A3-dependent myo-inositol auxotrophy in acute myeloid leukemia.

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    An enhanced requirement for nutrients is a hallmark property of cancer cells. Here, we optimized an in vivo genetic screening strategy in acute myeloid leukemia (AML), which led to the identification of the myo-inositol transporter SLC5A3 as a dependency in this disease. We demonstrate that SLC5A3 is essential to support a myo-inositol auxotrophy in AML. The commonality among SLC5A3-dependent AML lines is the transcriptional silencing of ISYNA1, which encodes the rate limiting enzyme for myo-inositol biosynthesis, inositol-3-phosphate synthase 1. We use gain- and loss-of-function experiments to reveal a synthetic lethal genetic interaction between ISYNA1 and SLC5A3 in AML, which function redundantly to sustain intracellular myo-inositol. Transcriptional silencing and DNA hyper-methylation of ISYNA1 occur in a recurrent manner in human AML patient samples, in association with IDH1/IDH2 and CEBPA mutations. Our findings reveal myo-inositol as a nutrient dependency in AML caused by the aberrant silencing of a biosynthetic enzyme

    Transcriptional dynamics during cell wall removal and regeneration reveals key genes involved in cell wall development in rice

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    Efficient and cost-effective conversion of plant biomass to usable forms of energy requires a thorough understanding of cell wall biosynthesis, modification and degradation. To elucidate these processes, we assessed the expression dynamics during enzymatic removal and regeneration of rice cell walls in suspension cells over time. In total, 928 genes exhibited significant up-regulation during cell wall removal, whereas, 79 genes were up-regulated during cell wall regeneration. Both gene sets are enriched for kinases, transcription factors and genes predicted to be involved in cell wall-related functions. Integration of the gene expression datasets with a catalog of known and/or predicted biochemical pathways from rice, revealed metabolic and hormonal pathways involved in cell wall degradation and regeneration. Rice lines carrying Tos17 mutations in genes up-regulated during cell wall removal exhibit dwarf phenotypes. Many of the genes up-regulated during cell wall development are also up-regulated in response to infection and environmental perturbations indicating a coordinated response to diverse types of stress

    Differential sensitivity of thick and thin fibers to HIV and therapy-induced neuropathy

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    The study assessed HIV-related and anti-retroviral therapy-induced neuropathy in myelinated and unmyelinated nerve fibers. One hundred consecutive HIV patients were examined clinically and standard nerve conduction velocities were measured. In addition, electrically induced sympathetic skin response (SSR) was assessed in the palms and soles. The difference in delay of SSR in palms and soles (Delta SSR) was calculated as an indirect measure of C-fiber conduction velocity. Thick fiber conduction velocities significantly decreased with age and increasing stage of the disease, whereas no effect of stage was found for Delta SSR (p=0.6). In contrast, medication of at least one of the most known neurotoxic drugs zalcitabine, stavudine, or didanosine did not result in significantly lower conduction velocities in thick fibers (51.29 +/- 3.4 m/s vs. 50.86 +/- 3.5 m/s), but was related to an increased Delta SSR. Delta SSR allows an indirect measurement of C-fiber conduction velocity. In HIV this measure of unmyelinated sympathetic fibers was most sensitive to anti-viral treatment whereas conduction velocity of myelinated somatic fibers was more sensitive to disease-related neuropathy. The results suggest that HIV neuropathy preferably affects myelinated and anti-retroviral therapy unmyelinated fibers. (c) 2007 Elsevier B.V. All rights reserved

    PGP 9.5 neuronal marker may differentiate immunohistochemically HIV-related from Mediterranean and immunosuppression-associated Kaposi's sarcoma

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    Mediterranean Kaposi's sarcoma (MKS), HIVrelated KS (HIV-KS) and immunosuppression-associated KS (IS-KS), caused by human herpes virus 8 (HHV-8), share similar histological features. The aim of this study was to investigate differences in epidermal nerve fibers (ENFs) between the three KS types and controls. Skin biopsies from 23 HIV-KS, 16 MKS, 28 IS-KS patients and 18 controls, age-gender matched, were immunostained with PGP 9.5; ENFs in upper epidermal layer (EL) and penetrating the basement membrane were measured. The mean number of nerve fibers penetrating ENFs was significantly lower in HIV-KS (p<0.001) compared to all other groups. MKS and IS-KS had comparable ENFs but lower than controls (p<0.00 1). In the upper EL all groups had comparable ENFs and lower than controls. In conclusion, HIV-KS can be distinguished histologically from other types, by counting ENFs. Moreover, KS is associated with decreased ENFs, which may be a histological reflection of nerve damage. This is even more pronounced in HIV-KS patients and could be explained by a neurotoxic action of HHV-8, HIV, and their co-existence. © Springer-Verlag Berlin Heidelberg 2013

    Aspects of the association between leishmaniasis and malignant disorders

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    Given the prevalence of leishmaniasis and cancer, the co-existence of these two diseases may be merely coincidental. However, a number of epidemiological, experimental and Laboratory studies suggest that an association between these two entities does exist. The aim of this review is to summarise the occurrence of leishmaniasis as an opportunistic infection associated with malignant disorders and to present the available literature potentially linking this infection with the development of cancerous lesions. We searched electronic databases and evaluated 37 studies involving 44 patients. Four different types of association between leishmaniasis and cancer were established: leishmaniasis mimicking a malignant disorder, such as lymphoma; leishmaniasis arising as a difficult to diagnose and treat infection among patients receiving chemotherapy for various malignant disorders; simultaneous diagnosis of leishmaniasis and a neoplastic disorder in the same tissue samples of immunocompromised patients; and direct involvement of Leishmania spp. in the pathogenesis/occurrence of malignant lesions, especially of the skin and mucous membranes. The main conclusion of this review is that leishmaniasis can directly or indirectly affect the presentation, diagnosis and course of various malignant disorders and it should be considered in the differential. diagnosis of malignancies in geographic areas where it is endemic and/or in patients with travel history to these areas. (C) 2007 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved

    An unusual case of brucellar spondylitis involving both the cervical and lumbar spine

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    We report an unusual case of brucellar spondylitis, involving both the cervical and lumbar spine. Diagnosis was established using magnetic resonance imaging (MRI). An initial plain radiograph of the lumbar spine, showing mild degenerative lesions, was misleading. Therefore, institution of a proper treatment was delayed. (C) 2001 Elsevier Science Inc. All rights reserved

    Chemotherapy ± cetuximab modulates peripheral immune responses in metastatic colorectal cancer

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    Objective: To identify changes in peripheral immune responses in patients with metastatic colorectal cancer (mCRC) treated with irinotecan/5-fluorouracil/ leucovorin (IFL) alone or in combination with cetuximab (C-IFL). Methods: Peripheral blood mononuclear cells (PBMCs) collected from healthy donors (n = 20) and patients with mCRC receiving treatment with either IFL (n = 30) or C-IFL (n = 30) were tested for cytokine production upon polyclonal stimulation with anti-CD3 monoclonal antibody, T cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR) and T regulatory cell (Treg) frequency. The respective results were evaluated over two treatment cycles and further assessed in relation to response to treatment. Results: PBMCs prior to treatment exhibited significantly lower production of IL-2, IFN-γ, IL-12 and IL-18 cytokines and lower auto-MLR responses, whereas Treg frequency, IL-4, IL-10 cytokines were increased compared to healthy donors. During treatment, IL-2, IFN-γ, IL-12, IL-18 and auto-MLR responses increased, while Treg frequency and IL-10 secretion decreased significantly compared to the baseline. Responders to treatment exhibited a significantly higher increase in IL-2, IFN-γ, IL-12 and IL-18 production and auto-MLR responses, and higher decrease in IL-4, IL-10 secretion and Treg frequency. Among all patient subgroups analysed, responders to C-IFL demonstrated significantly higher increase in auto-MLR responses, IL-12 and IL-18 secretion and higher decrease in Treg frequency. Conclusion: The disturbed immune parameters observed in patients with mCRC at presentation can be significantly improved during treatment with IFL and this effect can be potentiated by the addition of cetuximab. Monitoring of the peripheral immune system function could be used as surrogate marker in predicting treatment-related outcome. Copyright © 2013 S. Karger AG, Basel
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