17 research outputs found

    USP26 regulates TGF-ß signaling by deubiquitinating and stabilizing SMAD7

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    © 2017 The Authors. Published under the terms of the CC BY 4.0 license The amplitude of transforming growth factor-ß (TGF-ß) signal is tightly regulated to ensure appropriate physiological responses. As part of negative feedback loop SMAD7, a direct transcriptional target of downstream TGF-ß signaling acts as a scaffold to recruit the E3 ligase SMURF2 to target the TGF-ß receptor complex for ubiquitin-mediated degradation. Here, we identify the deubiquitinating enzyme USP26 as a novel integral component of this negative feedback loop. We demonstrate that TGF-ß rapidly enhances the expression of USP26 and reinforces SMAD7 stability by limiting the ubiquitin-mediated turnover of SMAD7. Conversely, knockdown of USP26 rapidly degrades SMAD7 resulting in TGF-ß receptor stabilization and enhanced levels of p-SMAD2. Clinically, loss of USP26 correlates with high TGF-ß activity and confers poor prognosis in glioblastoma. Our data identify USP26 as a novel negative regulator of the TGF-ß pathway and suggest that loss of USP26 expression may be an important factor in glioblastoma pathogenesis

    Low Levels of NDRG1 in Nerve Tissue Are Predictive of Severe Paclitaxel-Induced Neuropathy.

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    Sensory peripheral neuropathy caused by paclitaxel is a common and dose limiting toxicity, for which there are currently no validated predictive biomarkers. We investigated the relationship between the Charcot-Marie-Tooth protein NDRG1 and paclitaxel-induced neuropathy.Archived mammary tissue specimen blocks of breast cancer patients who received weekly paclitaxel in a single centre were retrieved and NDRG1 immunohistochemistry was performed on normal nerve tissue found within the sample. The mean nerve NDRG1 score was defined by an algorithm based on intensity of staining and percentage of stained nerve bundles. NDRG1 scores were correlated with paclitaxel induced neuropathy.111 patients were studied. 17 of 111 (15%) developed severe paclitaxel-induced neuropathy. The mean nerve NDRG1 expression score was 5.4 in patients with severe neuropathy versus 7.7 in those without severe neuropathy (p = 0.0019). A Receiver operating characteristic (ROC) curve analysis of the mean nerve NDRG1 score revealed an area under the curve of 0.74 (p = 0.0013) for the identification of severe neuropathy, with a score of 7 being most discriminative. 13/54 (24%) subjects with an NDRG1 score 7 (p = 0.017).Low NDRG1 expression in nerve tissue present within samples of surgical resection may identify subjects at risk for severe paclitaxel-induced neuropathy. Since nerve biopsies are not routinely feasible for patients undergoing chemotherapy for early breast cancer, this promising biomarker strategy is compatible with current clinical workflow

    NDRG1 expression in normal nerve tissue.

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    <p>Photo micrographs (x 40 objective) depicting NDRG1 IHC, scale bar is 50μm. A: Score 0: Nerve highlighted by circles, with no expression of NDRG1. B: Score 1: Minimal expression of NDRG1 in less than 50% of the nerve bundle. C: Score 2: Strong expression of NDRG1 in less than 50% of the nerve bundle. D: Score 3: Strong expression of NDRG1 in more than 50% of the nerve bundle</p
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