27 research outputs found

    C-fos upregulates P-glycoprotein, contributing to the development of multidrug resistance in HEp-2 laryngeal cancer cells with VCR-induced resistance

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    Abstract Background Laryngeal cancer tends to have a very poor prognosis due to the unsatisfactory efficacy of chemotherapy for this cancer. Multidrug resistance (MDR) is the main cause of chemotherapy failure. The proto-oncogene c-fos has been shown to be involved in the development of MDR in several tumor types, but few studies have evaluated the relationship between c-fos and MDR in laryngeal cancer. We investigated the role of c-fos in MDR development in laryngeal cancer cells (cell line: human epithelial type 2, HEp-2) using the chemotherapeutic vincristine (VCR). Methods HEp-2/VCR drug resistance was established by selection against an increasing drug concentration gradient. The expressions of c-fos and multidrug resistance 1 (mdr1) were measured using qPCR and western blot. C-fos overexpression or knockdown was performed in various cells. The intracellular rhodamine-123 (Rh-123) accumulation assay was used to detect the transport capacity of P-glycoprotein (P-gp, which is encoded by the mdr1 gene). Results HEp-2 cells with VCR-induced resistance (HEp-2/VCR cells) were not only resistant to VCR but also evolved cross-resistance to other chemotherapeutic drugs. The expressions of the c-fos and mdr1genes were significantly higher in the HEp-2/VCR cells than in control cells. C-fos overexpression in HEp-2 cells (c-fos WT) resulted in increased P-gp expression and increased the IC50 for 5-FU. C-fos knockdown in the HEp-2/VCR cells (c-fos shRNA) resulted in decreased P-gp expression and decreased IC50 for 5-FU. An intracellular Rh-123 accumulation assay showed that the mean intracellular fluorescence intensity (MFI) was lower in the HEp-2/VCR cells than in HEp-2 cells. C-fos WT cells also showed lower MFI. By contrast, c-fos shRNA cells exhibited a higher MFI than the control group. Conclusion C-fos increased the expression of P-gp and mdr1 in the HEp-2/VCR cells, and enhanced the efflux function of the cells, thereby contributing to the development of MDR

    Overexpression of GbF3′5′H1 Provides a Potential to Improve the Content of Epicatechin and Gallocatechin

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    The flavonoids in Ginkgo biloba L. (ginkgo) have important medicinal uses due to their antioxidant, antitumor, and blood circulation-promoting effects. However, the genetic mechanisms underlying flavonoid biosynthesis in ginkgo remain elusive. Flavonoid 3′, 5′-hydroxylase (F3′5′H) is an important enzyme in flavonoid synthesis. We detected a novel differentially expressed GbF3′5′H1 gene homologous to the F3′5′H enzyme involved in the flavonoid synthesis pathway through transcriptome sequencing. In this study, we characterized this gene, performed an expression analysis, and heterologously overexpressed GbF3′5′H1 in Populus. Our results showed that GbF3′5′H1 is abundant in the leaf and highly expressed during April. We also found four metabolites closely related to flavonoid biosynthesis. Importantly, the contents of 4′,5-dihydroxy-7-glucosyloxyflavanone, epicatechin, and gallocatechin were significantly higher in transgenic plants than in nontransgenic plants. Our findings revealed that the GbF3′5′H1 gene functions in the biosynthesis of flavonoid-related metabolites, suggesting that GbF3′5′H1 represents a prime candidate for future studies (e.g., gene-editing) aiming to optimize ginkgo flavonoid production, especially that of flavan-3-ols.Forestry, Faculty ofNon UBCForest and Conservation Sciences, Department ofReviewedFacult

    Rapid Pyrolysis of Wheat Straw in a Bench-Scale Circulating Fluidized-Bed Downer Reactor

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    The effects of acid washing treatment on the pyrolysis product distribution and product properties were investigated in a bench-scale circulating fluidized-bed (CFB) downer reactor with wheat straw as feedstock. The acid treatment not only removes most of the inorganic species present in the biomass but also alters the distribution of the remaining organic constituents. It was found that the removal of the inorganic species increases the yield of liquid product and reduces char formation and gas yield. CO and CO2 are the dominant components in the gaseous product, accounting for over 90?%. The concentration of CO in the gaseous product increases after acid treatment, while the CO2 concentration decreases. The oxygen and water contents in the liquid product are decreased on acid treatment, leading to a relatively high heating value and viscosity. More volatiles can be found in the char derived from the acid-treated wheat straw than from the raw wheat straw. This may suggest that a longer residence time is needed for pyrolysis of the acid-treated wheat straw in order to obtain the maximal yield of volatile matter

    A Novel Approach of Microstructure Refinement of TiAl in Laser Beam Welding

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    Grain refinement through borides is known to be suppressed when TiAl is welded with a laser beam. As β grains do not primarily nucleate on boride at a high cooling rate, a mixture of nitrogen and argon is applied as a protecting gas for the formation of TiN during solidification. The phase transformation is changed correspondingly from Liquid → Liquid + β → β → α + β → α + γ+ β → α2 + γ + B2 to Liquid → TiN + Liquid → β+ TiN → α + γ + TiN → α2 + γ+ TiN. It is found that β grains prefer to nucleate heterogeneously on the suspending TiN in the melt with orientation relationship {111}TiN//{110}β, leading to refined β grains. α2 colonies that were thus modified into fine non-dendritic grains. The effects of nitrogen as a shielding atmosphere on the microstructure evolution of TiAl are elaborately studied

    Sex-Related Differences of Ginkgo biloba in Growth Traits and Wood Properties

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    Ginkgo biloba is one of the most widely cultivated dioecious timber trees in China. Understanding sex-related differences and how they affect growth traits and wood properties is crucial for informed management and optimal utilization of ginkgoes. In the present study, we collected 42 ginkgo samples and conducted DNA molecular identification to determine their sex. The result was a 1:1 ratio of male to female specimens. In addition, we measured 16 growth-trait and wood-property indices for these samples using advanced equipment, such as X-ray diffraction (XRD) and the Hitman ST300 standing tree tool. For growth traits, significant differences were observed between male and female ginkgoes in terms of the diameter at breast height (DBH), clear bole height (CBH), height, and volume. Significant differences were identified in wood properties between male and female ginkgoes in terms of the degree of cellulose crystallinity (DCC), cell length, cell wall thickness, and wall-to-lumen ratio. Tracheids from female trees were found to be wider, with thicker cell walls, than those from male trees. Principal component analysis (PCA) showed that there was a slight separation between the sexes in terms of all growth traits, whereas there was no separation in wood properties. The membership function value (MFV) also showed that male ginkgo exhibited a more robust phenotype than female ginkgo. The selection of male ginkgo for breeding and utilization offers distinct advantages for practical production.Forestry, Faculty ofNon UBCForest and Conservation Sciences, Department ofReviewedFacult

    Characterization of the complete chloroplast genome of Cucun mismelo L. var. Agrestis Naud

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    Cucumis melo L. var. Agrestis Naud chloroplast genome sequence was first reported. The size of the chloroplast genome is 156,016 bp in length, including a large single copy region (LSC) of 86,334 bp, a small single copy region (SSC) of 18,088 bp, and a pair of inverted repeat (IRa and IRb) regions with 25,797 bp. Cucumis melo L. var. Agrestis Naud chloroplast genome encodes 133 genes, including 88 mRNA genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis with the reported chloroplast sequences shows that Cucumis melo L. var. Agrestis Naud was closely related to Cucumis melo subsp. melo
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