52 research outputs found

    The multi-targeted kinase inhibitor sunitinib induces apoptosis in colon cancer cells via PUMA

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    Constitutive activation of pro-survival kinases has become a promising target of small molecules with an increasing interest in developing multi-targeted agents. The mechanisms underlying the responsiveness to most agents targeting cancer specific survival pathways are still poorly understood but critical for their clinical application. In this study, we found that sunitinib, a small molecule inhibitor of multiple tyrosine kinases including VEGFRs and PDGFRs induces apoptosis and inhibits cell growth in colon cancer cells in cell culture and xenograft models via the BH3-only protein PUMA. Sunitinib treatment induced PUMA transcription via the AKT/FoxO3a axis. PUMA, BH3 mimetics, or 5-Flurourical sensitized colon cancer cells to sunitinib-induced apoptosis. Furthermore, PUMA was induced by sunitinib treatment in xenograft tumors, and deficiency in PUMA significantly suppressed the anti-tumor effects of sunitinib. Our study suggests that PUMA-mediated apoptosis is important for the therapeutic responses to sunitinib, and activation of the mitochondrial pathway by BH3 mimetics or PUMA manipulation may be useful for improving the antitumor activity of sunitinib. Modulation of PUMA and selective Bcl-2 family members might be potential biomarkers for predicting sunitinib responses. © 2012 Sun et al

    EZH2 or HDAC1 Inhibition Reverses Multiple Myeloma-Induced Epigenetic Suppression of Osteoblast Differentiation

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    In multiple myeloma, osteolytic lesions rarely heal because of persistent suppressed osteoblast differentiation resulting in a high fracture risk. Herein, chromatin immunoprecipitation analyses reveal that multiple myeloma cells induce repressive epigenetic histone changes at the Runx2 locus that prevent osteoblast differentiation. The most pronounced multiple myeloma-induced changes were at the Runx2-P1 promoter, converting it from a poised bivalent state to a repressed state. Previously, it was observed that multiple myeloma induces the transcription repressor GFI1 in osteoblast precursors, which correlates with decreased Runx2 expression, thus prompting detailed characterization of the multiple myeloma and TNFα-dependent GFI1 response element within the Runx2-P1 promoter. Further analyses reveal that multiple myeloma-induced GFI1 binding to Runx2 in osteoblast precursors and recruitment of the histone modifiers HDAC1, LSD1, and EZH2 is required to establish and maintain Runx2 repression in osteogenic conditions. These GFI1-mediated repressive chromatin changes persist even after removal of multiple myeloma. Ectopic GFI1 is sufficient to bind to Runx2, recruit HDAC1 and EZH2, increase H3K27me3 on the gene, and prevent osteogenic induction of endogenous Runx2 expression. Gfi1 knockdown in MC4 cells blocked multiple myeloma-induced recruitment of HDAC1 and EZH2 to Runx2, acquisition of repressive chromatin architecture, and suppression of osteoblast differentiation. Importantly, inhibition of EZH2 or HDAC1 activity in pre-osteoblasts after multiple myeloma exposure in vitro or in osteoblast precursors from patients with multiple myeloma reversed the repressive chromatin architecture at Runx2 and rescued osteoblast differentiation.Implications: This study suggests that therapeutically targeting EZH2 or HDAC1 activity may reverse the profound multiple myeloma-induced osteoblast suppression and allow repair of the lytic lesions

    Research Progress on Fermentation Strategies, Biological Activities and Quality Improvements of Fermented Fruit and Vegetable Juices

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    As the consumers pay more and more attention to a healthy diet, fermented fruit and vegetable juice related products with health benefits are attracting extensive notice. Fruits and vegetables are ideal substrates for microbial growth. Fermented fruit and vegetable juices are rich in nutrients with many function, adding more value to the products, which could have a broader market in the future. In this paper, the common fermentation strategies, the dominating bioactive ingredients, the functional activities and the effect of fermentation on the quality improvements of fermented fruit and vegetable juices are reviewed. Overall, this review has a guiding significance for the development of fermented fruit and vegetable juices industry

    Effects of mulching for water conservation on soil carbon, nitrogen and biological properties

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    The effect of mulching with straw, white plastic film and black plastic film for improving soil water storage and on the soil properties was examined in a wheat-maize rotation system on Loess soil in northwestern China. All the mulches improved the water storage to some extent and led to warmer soils. However, the organic C and total N contents of the soils declined significantly under the mulches, particularly the plastic film mulches, and this could have long-term detrimental effects on soil quality and the sustainability of the some mulching practices
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